Importing invoices into AP using VI

I've been working on this application that uses a SQL Server 2000 database connected to a VB front end using ODBC.

The issue is that I need to connect to MAS90 to either export some invoices or to use MAS90 with VI to import them from the SQL Server DB.

Currently the way I do it is to use VI to do an import into AP.INVOICE (Invoice data Entry file) from a table in the DB that has the following data:
Division, VendorID, InvoiceAmt, invoiceNum, Comment, invDate

When the import is run, I want it to create new invoices and and put them in a specific batch while this is being done.

However, when I run the import, it does not import lines into the invoice, only the header.
Additionally, even when i create a batch and then specify the batch when I do the import, it does not go into a batch.

Can anyone help me out. Or can anyone suggest a solution that would give me a little better integration like maybe if I can export stuff into MAS90 or maybe some programmers guide that explains to me how the data storage is organized so I could craft the export routine.

Thanks in advance