Hi Josh,
I've never used a Tyros, but as far as I can tell from looking at the manual there's no way to mute the CC#7 commands (volume pedal) sent over MIDI to the Rev2. Likewise, you can not mute the Rev2 from receiving without muting all other CC commands as well. If you set the Rev2 to NRPN instead of CC messages, it should mute the messages from the volume pedal, but then you mute the other CC messages too, except CC#1 I suppose.
You could add a midi filter to mute the CC messages you want, but that would mean having to pass the messages through a computer, which is probably not what you want.
May I ask what CC messages you want the Rev2 to receive from the Tyros, or what Rev2 parameters you use the Tyros to control by CC commands? Depending on what parameters and how few, perhaps there could be a workaround, don't get your hopes up, but just maybe.