When I use the ~C1,127 command (as technique text) in sibelius, it only plays back correctly in VDL2 about 50% of time.

Does anyone know if this is a VDL2 or sibelius issue, and more importantly, how to fix it?

Where exactly are you entering the controller change in relation to the first note of the change?  The message has to be slightly ahead of where you want the change to occur.

it will work 50% of the time of you don't also set the mod wheel setting you want before it, or at the beginning of the score.  If you start playback at a point that doesn't change the setting from the last time you played it, you won't hear the correct changes.

Thanks guys! I'll set the midi message ahead of time from now on! I had been placing it right ontop of the note I wanted to modulate.