Jos, I am aware of what you are saying. When using a specific sampler or wavetable you need to determine what is in what bank, e.g., 1-128 or 0-127. In addition, Yamaha often, as you say, uses their drums from bank 127. The styles would need to be changed to accommodate this. This is the easy part.
The hard part is to get the drum instruments for XG to line up with the GM note numbers. For instance, brush tap, brush swirl, brush slap for the Brush Kit need to be on the appropriate note numbers on the GM Brush Kit. I know these do not line up between the XG and GM Brush Kits. There are a number of other examples within every drum kit that should be translated.
It, of course, would be nice to get this done but I can do without and continue to use LiveSynthPro or VSampler with the sYnerGiGS Wavetable. With the substitutions and changes in instruments I have made this wavetable is noticeably better than the top of the line arranger keyboards.
Bluezplayer, I have not as yet upgraded to JammerPro 5.0. I have checked the changes and think it is a significant improvement over the previous already a very good program. I will be upgrading shortly. In addition, I am waiting for the JammerLive update - Windows XP & JammerPro style compatibility.