Need Help: Logic Express - Input / Output Options

[Doc Rock]

Here's a question from a digital recording illiterate:

Does anyone know how to get Logic Express (7) to accept incoming signals via USB, but use the internal audio port as the output for monitoring at the same time.
I am using several USB devices to feed into my Mac. Switching the core audio driver handles that quite acceptable. However, I can't monitor recorded tracks, if the input devide I am using (i.e. Tascam U122) won't allow a return signal.

It worked perfectlt on good old Garageband, because that program let's you define in- and output separately.

Any idea how I can get this fixed in Logic?

Thanks!