Has anyone been able to send their vendor credits through for an approval? I know there are limitations with this trx type, but figured I'd see if there were any success stories out there...

I normally suggest using an RMA process as an "approval" flow.

That's what I have used in the past too, but doesn't it end up with a credit anyway? How do you prevent credits being created without an RMA?

"created from : type <> 'Return Authorization" or something to that effect.

But does that prevent a user from being able to do it?

with a workflow? Sure.

Hmm.. Will give it a try.