BOM Header Row with Custom Property

I'd like to have my BOM Header Row display "XXX-YYY CONTAINS:" where XXX-YYY is a Custom Property called Part Number from the model in the view selected for the BOM. The reason is that I might have two different assemblies from the same family of parts on one drawing, so I need XXX-YYY to change depending on which view is selected for the BOM. 
Right now, when I enter the linked property text into the header row by using Model found here -> Selected component or other drawing view -> Part Number (the custom property), it works just fine, so I save the BOM as a template. But, the next time I insert the BOM using the saved template, the field disappears and it just says " CONTAINS:". Rebuild does nothing. How do I get the custom property to auto-populate every time I insert a BOM? Seems like this should be a pretty common need...