Just tested my fast track pro with realband all working ok. In the fast track pro properties in the control panel of windows I have ticked under channels in bandwidth dialog
outputs 1 and 2 (balanced and unbalanced)
outputs 3 and 4 (s/pdif balanced and unbalanced)
balanced input 1 (mono)
balanced input 2 (mono)

only thing not ticked there is
s/[pdif input (stereo)
sample rate is 44.1

fast track is set there to record at 24 bit, at 16 bit in realband but will record at 24 bit too, after checking the above maybe change the bit depth in realband to 16 bit.

My fast track needs to be switched on before I open realband, if I switch on after I open realband then fast track won't be detected.
I need to close down realband and then open again and it dectects the fast track and records fine.
another thing to try is reinstall realband.

musiclover