How to include invoice attachments from UCM on bursted email output

I have created a custom email notification for invoices requiring receipts. I am using an RTF template for the email body and would like to include manually uploaded invoice attachments with the notification. So far I am not having any luck including PDF attachments on the bursted emails. Is it possible to include manually uploaded invoice attachments on bursted BIP output? If so can anyone confirm how to identify the correct document ID to use? Per Doc ID 2550855.1 this is the query I am using in the bursting definition to pull the attachments:

select b.invoice_id, b.invoice_num, min(c.dm_version_number)