Hey,
The command for effect select is 
- Code: Select all
 EFFSELECT
To set for example the effect for player 1 you can write the following commands (the MIDI note is an example)
- Code: Select all
 # 90 a1 7f      EFFSELECT  1   1.000000   0
This is not the complete code for all this is only the press function. This is for player 1 and effect deck 0 (default).
Value 1 = increase / decrease the effect
Value 2 = Active effect (0 to 5)
If it work like you want I can't say. I have two buttons to step trough all the effects.
I hope it will help you.
Regards
Christian