You are correct. Can not be done. On the 8100 it has 4 different colored LED's under the track ball and the app selects which one to lite. On the 8130, we only have the white. Sorry!
Seriously though, there are like 5 threads just on this one subject... I suggest searching next time... most of the hits that come up give you helpful alternatives... like tips on colouring your LED, or things like that...
Darn right? So frustrating they stopped it with out models!! oh well we have better cameras and GPS and etc