There's a button for using the commorose, so that's probably just unavailable for the Beta.
My problem with BF3 is that the movement feels very sluggish and weird. I've tried messing with the mouse sensitivity and toggling the "raw feed" setting on and off, but so far - nothing. Still feels like I'm trying to move a marionette.
Second problem is my computer shutting down after a couple of minutes of playing, probably due to overheating. I'll have to lower the graphics, I guess. It's annoying having to join a server and spawn before being able to change any settings, though.