Our company's using ServiceNow to track incidents reported by users. To keep an eye on call resolution our helpdesk look at a backlog chart to keep an eye on trends. The backlog chart is produced using the same code as is available here: http://wiki.servicenow.com/index.php?title=Custom_Chart_Rendering
I was recently asked to look into filtering this graph by category, so that we can focus on incidents for particular applications. I've tried a few options but can't find anything which successfully filters the data. My best bet at present is that I need to apply the filters to the summary set, but even with admin access I'm unable to edit summary sets (I can't say if this is an issue with our setup or by design as I don't have much experience with this system / any with this API).
Thanks in advance for any pointers / suggestions.