Powershell find and replace text that spans two lines

Question

I have this unusual XML data structure, where I need to update the Job Number attribute value.

<?xml version="1.0"?>
<MiscContainer version="2018-1">
  <Object name="MainObject" type="TDM_Container">
    <Object name="OrderList" type="TDM_List_Order">
      <List name="Items">
        <Object type="TDM_Item_Order">
          <Property name="TraySystemType" value="stNone"/>
        </Object>
      </List>
    </Object>
    <Object name="CustomDataList" type="TDM_List_CustomData">
      <List name="Items">
        <Object type="TDM_Item_CustomData">
          <Property name="CustomDataID" value="CDAB5D3000B66D45D69F4F27074E55E0D8"/>
          <Property name="FieldCaption" value="ZB Encode Account#"/>
          <Property name="Value" value="New"/>
          <Property name="Kind" value="cdkPublic"/>
        </Object>
        <Object type="TDM_Item_CustomData">
          <Property name="CustomDataID" value="CDB0C755BF8BEB45419DED0B8D4A5CF8B4"/>
          <Property name="FieldCaption" value="PO#"/>
          <Property name="Value" value="000009"/>
          <Property name="Kind" value="cdkPublic"/>
        </Object>
        <Object type="TDM_Item_CustomData">
          <Property name="CustomDataID" value="CDB10DBE4FD0BD4CAA96B22AA6CD9A83C2"/>
          <Property name="FieldCaption" value="Job Number"/>
          <Property name="Value" value="1234"/>
          <Property name="Kind" value="cdkPublic"/>
        </Object>
        <Object type="TDM_Item_CustomData">
          <Property name="CustomDataID" value="CDD69CA4A79BE145369C3FD889E18E0BCF"/>
          <Property name="FieldCaption" value="coupon 1"/>
          <Property name="Value" value="3123213"/>
          <Property name="Kind" value="cdkPublic"/>
        </Object>

I couldn't figure it out using an XML object, so I tried to use just the string replace function. The problem with the replace function is I need to search across two lines to find the unique match. I used a regex expression (.*) to handle the possibility of there not being a value there at all, but I need to insert a value.

Here is my code:

$Folder = '\\3ipbg-fs-p01\private\UDI-Data-3i-Dev\inbound\archive\'

Get-ChildItem $Folder | ForEach-Object -Process {
    if ($_.PSIsContainer) {
        $sFolderPath = $_.FullName
        $sFolderName = Split-Path $sFolderPath -Leaf

        Get-ChildItem $sFolderPath | Where {
            $_.Name -like $sFolderName + '.xml'
        } | foreach {
            $sFilepath = $_.FullName

            (Get-Content $sFilepath) -replace '<Property name="FieldCaption" value="Job Number"/>
          <Property name="Value" value="(.*)"/>','<Property name="FieldCaption" value="Job Number"/>
          <Property name="Value" value="1234"/>' | Out-File -Encoding Ascii $sFilepath
        }
    }
}

But it doesn't work, I think because of the CR and LF. Just for testing purposed, if I remove the multi-line, it works, but I need the multi-line because single line is not unique.

Hoping someone can help either with the string replace or the XML route.