And there is on occasion a style that wants to default back to the original drums even after you change and regen it. Its rarely occurs and I've seen it mostly when the style had a multi-drum option. I've worked around it by making one of the other tracks an RD track. Right click on any track in the "mixer" and select "choose RealDrums." Make sure the cursor is in the long black bar where the title of the RD or RT appears when you right click.

Bud