I don,t use FM so I will wait and see what other responses you get.
But, in the meantime, I will say that depending on the machine, I use either PulseAudio or QasMixer.
In general, I have never found an audio device that does not show in QasMixer and allow you all the control you want for it.
I don't know if it is part of the FM install.
If you do not get some more knowledgeable advice, I will boot my FM disk and do some playing later.