You used to be able to unlink the stereo input pairs in the UA-101 mixer/driver application if you needed to control channels seperately in that.
Sonar treats the inputs as 1L, 1R and the combination as 1 stereo, but you can point one track's input at either of the "pairs" and another at the other so Sonar handles the inputs as mono ones.
As for the driver, the UA series interfaces were originally made by Edirol. Then Roland took Edirol over and acquired Cakewalk and decided to re-badge the interfaces as "Cakewalk", though Cakewalk didn't maintain the drivers, Roland did. Roland later discontinued them and replaced them with interfaces badged as Roland. When Cakewalk became part of the Gibson group the interfaces and responsibility for their drivers stayed with Roland.
So any requests for modification to the drivers or software for the UA series need to go to Roland.