Importing Subs (using iDMS) without creating invoices

We have a new client who is moving to iMIS from an alternate system.

I wish to import their current years subscription data into iMIS as a starting point for their first member renewals in iMIS.

I have ran several import tests using iDMS (Power Suite) into their DEV environment. The imports came in as expected. However, iMIS is also generating invoices for every import.

I have tried setting the Bill Subscription flag to False during the import, but the invoices are still appearing.

Is there a way to import sub lines without creating 1000's of invoices? I want their finances to start fresh, as these invoices already exist in another system.