AME approval for ERS- autoinvoice program created invoices?

Dear All,

I want to approve PO/Receipt matched invoice via AME while invoice is being created by Pay on Reciept ang autoinvoice scenario.

This gives us two types of PO matched invoices one with selfbilling (Pay on reciept automated created invoice) and other with normal POapprval invoice from invoice workbench.

The only difference between two invoices i seen is of LINE_SOURCE i.e IMPORTED in case of self billing and in other it is HEADER MATCH.

AME provides a attribute SOURCE at header level and SUPPLIER_INVOICE_LINE_SOURCE at line level. SUPPLIER_INVOICE_LINE_SOURCE, now my question is how can i use these attributes to get approval for SOURCE ERS (HEADER) and LINE_SOURCE i.e IMPORTED invoices also with the  parallel approvals of HEADER MATCH both having different approval groups.