UBR - UER for converted projects

Hello

We are trying to define conversion strategy for Projects & AR. Now think of following scenario --

Project already billed for $100,000 (thr non oracle system bfor conversion)

Thus in GL --

 Receivable -- 100000 Dr

Unearned Revenue -- 100000 Cr

But when I try to recognize revenue in Oracle PA; It does following (since billing is not done thr OPA)

Revenue --- 100000 Cr

Unbilled Receivables --- 100000 Dr

How to fix this; as we need to charge UER instead of UBR in above scenario...

One way may be to Recognize rev with diff event type which uses twicke AA rules.

But that does not have any control for users to select the event types...