I'm riding a 2008 GF Paragon with SRAM X0.9 shifters. Love the bike on the snowy trail commute, but the shifters quit working when it's colder than -20F. The problem is that the shifter won't release the cable to shift to smaller sprocket; the release trigger won't move. All other parts of the system work: I can shift up, if I release tension on the cables the derailers move. It's in the shifter mechanism. The shop had the bike and they worked on it (WD40 in the shifter housing), and there seemed to be some improvement, but only by a couple of degrees. I posted this in the mechanics forum and got no answers, so thought that I'd come here.

Anybody out there suffering similar problem?
Better yet anybody found a solution (other than not riding when it is that cold)?