Change from iOS Developer Program to Enterprise

I have enroled in iOS Developer Program. I'm creating a simple location app, but it is targeted for our company employes only. Now, I've figured out that I enroled in the wrong program, as it should have been Enterprise. I'm certain that my app will never pass in App Store review.

My question is if there's a migration path, where I could use my already paid $99 to change to the $299 Enterprise account. What will it take for me to do it?

Thanks.