I am running the latest beta, and the "Cold and Dark" modified Cessna 172.
I set up an IFR flight with two VORs - John Wayne (KSNA) to Santa Monika (KSMO).
I was able to tune the NAV 1 VOR for the first waypoint, using the mousewheel over the radio tuning knobs, but I couldn't tune the NAV 2 radio, even though the mousewheel symbol was displayed over its tuning knobs.
Is this a known limitation in this Early Access version of Aerofly FS2?