Can you tell us in detail what is the issue you are facing?
Are you using the SDK 3.5 bundled with FB?
I have not had any issues so far in the short time I have used FB4.
I would like to use the new FB4 IDE but cant upgrade the SDK at the moment.
It will potentialy also be an environment with mixed IDEs using both FB3 and FB4.
So I am wondering if there are any known issues with the set up FB4 + sdk3.5 in general.