Pressing CTRL-F on my keyboard does a 30-second-skip, a really useful feature, in Windows Media Center. I tried to map a button on my remote to CTRL-F, but it doesn't seem to work in WMC. I'm not using one of the off-frequency remotes; I've programmed my Logitech Harmony to use one of the suggested brands, which I feel certain uses signals near the 38kHz range.
The weird thing is, it seems to have mapped the CTRL-F button correctly -- I can open up Wordpad and press my "30s skip" button, and the "Find" dialog opens. However, when Windows Media Center is playing content, the button is tot