Axegrinder - hearing sound through the headphones on the Alpha doesn't mean that signal is getting to the computer - the Alpha has direct hardware monitoring. In order to hear if the signal is passing through to the computer and back, you need to rotate the monitor mix knob fully clockwise to the playback side of the dial.

If not, then you are just passing signal from the input of the alpha directly to the headphone jack.

Once you have done that - then there is some debugging about how to get the driver / mixer applet (I don't believe there is one for the Alpha) to function correctly in RB for your Alpha, so that you can ensure you are recording signals.

Unfortunately, it looks as if Lexicon have chosen to give instructions in the manual for the operation of the interface strictly for Cubase LE. That's kind of unfortunate.

-Scott