Customizing PO Confirm Receipt Workflow notification

 Hi,
I'm trying to customize the "PO Confirm Receipt (PORCPT)" workflow notification. The requirement is to add a link to the "PO document" under the "Related Application" section.
This section already has a "Return to Receiving" Link, but I'm unable to figure out how to add another link and where to set it's value. 

I found that this region is a AK region called WFNTFDETAILSATTACH. But I have no idea how to add another link to this same region.
Any help in this would be greatly appreciated.

Thanks,
Ashish