CM10.1 now cannot record any inbound audio on phone calls
The issue is related to, as far as I know, Cyanogenmod policies.. In some countries call recording is illegal and therefore CM team hasn't implemented this feature. It's really annoying because the issue applies to certain (but not all) regions of the world.

I do hope that CM developers will come up with some sort of hack in the future. For now I am using Auto Call Recorder (https://play.google.com/store/apps/details?id=com.appstar.callrecorder) and using Mic as a source. The volume of inbound audio is very low unless the mic is turned on during the call.

Call recording is the only feature I lack in CM...