I have a Hauppauge WinTV PVR-150 MCE card, and I experience the exact same problem.
The FM radio tab is only visible once.
These are the steps to reproduce:
* Add an AnalogTV instance.
* In the configuration that appears, select Antenna, and Sweden. Note that FM radio is unsupported.
* Click Save and immediately Re-open. Now FM radio is supported.
Each time that I access the configuration page after this time, FM radio is reported to be unsupported.
Could this be fixed in a future release?