Sound button in ENV not working

[Guuz]

I want to assign a different sound to the rim of a tom, but it's not working?
When I press the More button Ican hear the sound I want, but when I hit the rim I hear the sound from the pad?
When I go to the envelope page I cannot change the sound + button to ++

Any ideas what I'm doing wrong?

Cheers!

[Coda]

A + (and not a +- or -+ or ++) indicates that the sound only has a single zone in it.
To assign a different sound to the rim, you press KIT, press DOWN, either hit the rim or press MORE and the TOM you want to assign a new sound to, to make sure it's selected and locked, then use the dial on the left to select the sound you want. A click down on the left knob allows you to change sound folders for quicker navigation.