DSLR cameras offer much more manual control over the camera settings, to support e.g. RAW files and bracketing. The CHDK (Canon Hacker Development Kit) software makes the extra settings of a DSLR available on Canon's point-and-shoot cameras.
I've read through it, specifically pages 84-86 that detail using the rear wheel to select the RAW format and the left-right buttons to select the JPEG format. In any mode -- including P, Av & Tv -- rotation of the rear wheel doesn't affect the RAW selection; in the RAW selections the highlighted cursor remains to the far left of the screen over