I had somehow the same idea of sending MIDI CC from Sylphyo buttons.
I am playing the Trombone from samplemodeling. This virtual instruments allows changing of different kinds of mutes via a specific CC. Different values would activate different mutes.
This is the solution I found:
I am hosting samplemodeling's SWAM engine with the trombone inside Cantabile Software. Cantabile allows me to implement MIDI filters which would transfer certain notes into MIDI CC with specific parameters. So I configured the lowest notes to generate those MIDI CC and am now able to change mutes simply by playing one of the lowest notes.
This works well with one disadvantage: If you use the transpose function of Sylphyo, the controlling notes are also transposed. So, I ended up with configuring two sets of instruments inside Cantabile: one set with C tuning and one set with Bb tuning. This concept now works fine for me.