Need to automatically source the BPA details for a specific item or category

Hi All,

I have created a Blanket Purchase Agreement (BPA) and i have specified two lines within in
First Line has an Item specified
Second Line is specified with a category.

When i create a requisition and specify the Item in the first line , it popups the message stating that there is a BPA already existing and all the details get automatically populated in the source details tab and in the following fields
Document Type
Document
Line
But when i create the second line for category based requisition , there is no popup getting displayed even when there is BPA associated to it.