Jun 10, 2008 07:31 pm It may depend on your keyboard, but I think in general you won't need to worry about midi-thru unless you're sending another midi device through it to the interface.
So, you should be able to connect the Midi-out on the keybaord to the midi-in on the interface, make sure it's enabled in FL Studio, and you should be good to go.
You may need to set it as generic controller, or if it's a dedicated midi-controller with its own drivers, FL Studio should detect it.
-J