Okay, I'm using a Line 6 UX2 and Acid 7 Pro and a little modeling program that I fould called TH1 Overloud. It's kinda cool, I find it easy to work with, and the sounds are nice. However, for some strange reason, the UX2 is always using active input channels 3 & 4, which I can't seem to select in acid because Acid won't let me select the ASIO UX2 as the input source (I'm pretty sure that once I've selected it, I'd have options to change the channels, I'm guessing that Acid is using 1 & 2 by default).
I see the ASIO UX2 on the list of available inputs, but when I click on it, nothing happens and the input doesn't change. It's like it just wants to ruin my day or something.
I know that ACID isn't the best recording program, but I'm really familiar with it, so I wanna stick to my guns for the time being.
In general, though, I've had a lot of trouble with getting Acid to recognize things and getting it to actively monitor my playing (it does the same thing when I try to turn active monitoring on... it just doesn't do anything when I click the option)
If Acid is causing you that much trouble maybe you should consider removing yourself from your comfort zone and switching to a more capable DAW.

Theres a learning curve but its better in the long run instead of resting on your laurels.