Technical issues in customize email attachment functionality for finalize billing Invoice

Hello Friends

I need a technical help to overcome this issue.

Here is our customer requirement and the issues we are facing.

 

This is in PeopleSoft 9.0 FSCM env.

 

After an invoice has been Finalized, Customer would like to email the invoice to the customer; this is delivered functionality in 9.1 and will be implemented during the upgrade. 

 

In 9.0, we are working to create a limited modification to email a finalized invoice (bill) to the email address associated with the primary contact for the customer. 

 

In implementation stage, customer has already has define a JOB(BIJOB51) which contains the invoice finalize process along with couple of Crystal invoice formats for different BUs.