Just a little bit. All ca-modules don't support the multiple channel thing. They can just handle one channel at a time.It works for me with FloppyDTV and Conax 4.
I can view one channel and record another as long as they are on the same Mux or whatever its called.
I Use TV3.
Or did I missunderstand the question maybe.
But you say you can record and watch at the same time. So here comes my question. What brand do you have on your ca-module for conax? Have you tried to record more than 2 channels from the same mux?