Primefaces StreamedContent handling when using ui:include or composite component

Question

I stream images and pdf with StreamedContent from primefaces which works so far. I handle the streaming described in Primefaces StreamedContent

public StreamedContent getStreamedImageById() {
    FacesContext context = FacesContext.getCurrentInstance();

    if (context.getCurrentPhaseId() == PhaseId.RENDER_RESPONSE) {
        // So, we're rendering the view. Return a stub StreamedContent so that it will generate right URL.
        return new DefaultStreamedContent();
    }
    else {
        // So, browser is requesting the image. Get ID value from actual request param.
        String id = context.getExternalContext().getRequestParameterMap().get("id");
        Image image = service.find(Long.valueOf(id));
        return new DefaultStreamedContent(new ByteArrayInputStream(image.getBytes()));
    }
}

Now I included the corresponding xhtml in two places with ui:include and created with CDI two separate instances of the backing bean. I pass the correct instance with ui:param:

<ui:include src="/sections/content/contentViewer.xhtml">
    <ui:param name="beanBL" value="#{editPropertyContentBL}" />
</ui:include>

And use the passed bean in the xhtml (here a short part of it):

<ui:composition xmlns="http://www.w3.org/1999/xhtml" xmlns:ui="http://java.sun.com/jsf/facelets"
xmlns:f="http://java.sun.com/jsf/core" xmlns:p="http://primefaces.org/ui" xmlns:h="http://java.sun.com/jsf/html"
xmlns:o="http://omnifaces.org/ui" xmlns:pe="http://primefaces.org/ui/extensions">

<h:panelGroup id="contentViewerOuterId"
    rendered="#{not beanBL.isSelectedContentMimeTypeStartsWith('text/')}">

    <!-- pdf content -->
    <pe:documentViewer id="docViewerId" value="#{beanBL.inlineContent}"
        rendered="#{beanBL.isSelectedContentMimeTypeStartsWith('application/pdf')}" />
...

By passing the bean instance as ui:param the else-part of the backing bean stream handling code is never executed. I get a NPE (this is the full stacktrace):

12:41:19,368 ERROR [org.apache.catalina.core.ContainerBase.[jboss.web].[default-host].[/App].[Faces Servlet]] (http-/0.0.0.0:9090-6) JBWEB000236: Servlet.service() for servlet Faces Servlet threw exception: java.lang.NullPointerException
at org.primefaces.application.resource.StreamedContentHandler.handle(StreamedContentHandler.java:56) [primefaces-5.1.17.jar:5.1.17]
at org.primefaces.application.resource.PrimeResourceHandler.handleResourceRequest(PrimeResourceHandler.java:84) [primefaces-5.1.17.jar:5.1.17]
at javax.faces.application.ResourceHandlerWrapper.handleResourceRequest(ResourceHandlerWrapper.java:153) [jsf-api-2.2.11.jar:2.2]
at javax.faces.webapp.FacesServlet.service(FacesServlet.java:651) [jsf-api-2.2.11.jar:2.2]
at org.apache.catalina.core.ApplicationFilterChain.internalDoFilter(ApplicationFilterChain.java:295) [jbossweb-7.2.2.Final-redhat-1.jar:7.2.2.Final-redhat-1]
at org.apache.catalina.core.ApplicationFilterChain.doFilter(ApplicationFilterChain.java:214) [jbossweb-7.2.2.Final-redhat-1.jar:7.2.2.Final-redhat-1]
at org.primefaces.webapp.filter.FileUploadFilter.doFilter(FileUploadFilter.java:72) [primefaces-5.1.17.jar:5.1.17]
at org.apache.catalina.core.ApplicationFilterChain.internalDoFilter(ApplicationFilterChain.java:246) [jbossweb-7.2.2.Final-redhat-1.jar:7.2.2.Final-redhat-1]
at org.apache.catalina.core.ApplicationFilterChain.doFilter(ApplicationFilterChain.java:214) [jbossweb-7.2.2.Final-redhat-1.jar:7.2.2.Final-redhat-1]
at ip.client.commons.web.xss.filter.XSSFilter.doFilter(XSSFilter.java:53) [ip-filter-xss-4.3.0.jar:4.3.0]
at org.apache.catalina.core.ApplicationFilterChain.internalDoFilter(ApplicationFilterChain.java:246) [jbossweb-7.2.2.Final-redhat-1.jar:7.2.2.Final-redhat-1]
at org.apache.catalina.core.ApplicationFilterChain.doFilter(ApplicationFilterChain.java:214) [jbossweb-7.2.2.Final-redhat-1.jar:7.2.2.Final-redhat-1]
at org.omnifaces.filter.CharacterEncodingFilter.doFilter(CharacterEncodingFilter.java:115) [omnifaces-1.8.1.jar:1.8.1-20140603]
at org.omnifaces.filter.HttpFilter.doFilter(HttpFilter.java:77) [omnifaces-1.8.1.jar:1.8.1-20140603]
at org.apache.catalina.core.ApplicationFilterChain.internalDoFilter(ApplicationFilterChain.java:246) [jbossweb-7.2.2.Final-redhat-1.jar:7.2.2.Final-redhat-1]
at org.apache.catalina.core.ApplicationFilterChain.doFilter(ApplicationFilterChain.java:214) [jbossweb-7.2.2.Final-redhat-1.jar:7.2.2.Final-redhat-1]
at ip.client.web.filter.commons.AbstractFilter.doFilter(AbstractFilter.java:106) [ip-filter-commons-5.0.0-SNAPSHOT.jar:5.0.0-SNAPSHOT]
at org.apache.catalina.core.ApplicationFilterChain.internalDoFilter(ApplicationFilterChain.java:246) [jbossweb-7.2.2.Final-redhat-1.jar:7.2.2.Final-redhat-1]
at org.apache.catalina.core.ApplicationFilterChain.doFilter(ApplicationFilterChain.java:214) [jbossweb-7.2.2.Final-redhat-1.jar:7.2.2.Final-redhat-1]
at org.omnifaces.filter.CharacterEncodingFilter.doFilter(CharacterEncodingFilter.java:115) [omnifaces-1.8.1.jar:1.8.1-20140603]
at org.omnifaces.filter.HttpFilter.doFilter(HttpFilter.java:77) [omnifaces-1.8.1.jar:1.8.1-20140603]
at org.apache.catalina.core.ApplicationFilterChain.internalDoFilter(ApplicationFilterChain.java:246) [jbossweb-7.2.2.Final-redhat-1.jar:7.2.2.Final-redhat-1]
at org.apache.catalina.core.ApplicationFilterChain.doFilter(ApplicationFilterChain.java:214) [jbossweb-7.2.2.Final-redhat-1.jar:7.2.2.Final-redhat-1]
at org.omnifaces.filter.GzipResponseFilter.doFilter(GzipResponseFilter.java:149) [omnifaces-1.8.1.jar:1.8.1-20140603]
at org.omnifaces.filter.HttpFilter.doFilter(HttpFilter.java:77) [omnifaces-1.8.1.jar:1.8.1-20140603]
at org.apache.catalina.core.ApplicationFilterChain.internalDoFilter(ApplicationFilterChain.java:246) [jbossweb-7.2.2.Final-redhat-1.jar:7.2.2.Final-redhat-1]
at org.apache.catalina.core.ApplicationFilterChain.doFilter(ApplicationFilterChain.java:214) [jbossweb-7.2.2.Final-redhat-1.jar:7.2.2.Final-redhat-1]
at org.apache.catalina.core.StandardWrapperValve.invoke(StandardWrapperValve.java:230) [jbossweb-7.2.2.Final-redhat-1.jar:7.2.2.Final-redhat-1]
at org.apache.catalina.core.StandardContextValve.invoke(StandardContextValve.java:149) [jbossweb-7.2.2.Final-redhat-1.jar:7.2.2.Final-redhat-1]
at org.jboss.as.web.security.SecurityContextAssociationValve.invoke(SecurityContextAssociationValve.java:169) [jboss-as-web-7.3.0.Final-redhat-14.jar:7.3.0.Final-redhat-14]
at org.apache.catalina.core.StandardHostValve.invoke(StandardHostValve.java:145) [jbossweb-7.2.2.Final-redhat-1.jar:7.2.2.Final-redhat-1]
at org.apache.catalina.valves.ErrorReportValve.invoke(ErrorReportValve.java:97) [jbossweb-7.2.2.Final-redhat-1.jar:7.2.2.Final-redhat-1]
at org.apache.catalina.core.StandardEngineValve.invoke(StandardEngineValve.java:102) [jbossweb-7.2.2.Final-redhat-1.jar:7.2.2.Final-redhat-1]
at org.apache.catalina.connector.CoyoteAdapter.service(CoyoteAdapter.java:336) [jbossweb-7.2.2.Final-redhat-1.jar:7.2.2.Final-redhat-1]
at org.apache.coyote.http11.Http11Processor.process(Http11Processor.java:856) [jbossweb-7.2.2.Final-redhat-1.jar:7.2.2.Final-redhat-1]
at org.apache.coyote.http11.Http11Protocol$Http11ConnectionHandler.process(Http11Protocol.java:653) [jbossweb-7.2.2.Final-redhat-1.jar:7.2.2.Final-redhat-1]
at org.apache.tomcat.util.net.JIoEndpoint$Worker.run(JIoEndpoint.java:920) [jbossweb-7.2.2.Final-redhat-1.jar:7.2.2.Final-redhat-1]
at java.lang.Thread.run(Thread.java:745) [rt.jar:1.7.0_75]

If I remove the ui:param and use the cdi bean name directly in the included xhtml, the if-part is executed first and the else part afterwards and it works. I don't understand that. Maybe somebody can explain that?

Thanks Oliver