Hi John,
I have looked at the 'UnpluggedBallad' style in MixMaster, which reveals the following.
In the style, there are notes on the Pad channel (in this case Ch5 and Ch14) in the following sections only: Intro3, Main Variations C and D, Fill In C and D, Break, and Ending 3.
If you start the style and select any of the above style sections, you should hear the strings voice (KinoSmall - Mega Voice) used for the Pad part.
There are no notes for the Pad channel in Main Variation A or B, Intro1 or 2 , Ending1 or 2 or Fill In A or B.
If you select any of these sections when the style is running, you won't hear anything from the Pad part. It won't matter if you change the voice, you still won't hear anything because there is no note data to play! I suspect that you are selecting Main A or B.
If you want to have the Pad part play in Main A and B, you could copy the Pad part from Main C or D into Main A and B using the keyboard's 'Style Assembly' function in 'Style Creator'. All 4 Main sections are the same length (4 bars) so it is very simple to do this.
What you are hearing when you play a chord when the ACMP button is on but the style is not running, is the so called 'Stop ACMP' Pad and Bass voices. These voices depend on the current Stop ACMP setting. See page 11 of the 'Genos Reference Manual' for the options that you can select for 'Stop ACMP'. I think the default setting is 'Fixed'.
So it looks as if you can put the bug spray away for now!
Regards
Ian