It works. A fine mesh brew bag would also work (check your LHBS). Use it to line the inside of the keg then place your "out" portion of your auto siphon hose at the bottom, inside the bag. Siphon normally, then gently lift out the bag when you're done.
Alternatively, gently submerge the bag in your fermenter and put the "in" side of the auto siphon in the center of the bag. I'd probably do this method as it seems like lifting the bag out of the keg would cause a little more splashing and runoff than i'd like. The hops trub is going to have absorbed a good bit of beer and when lifting the bag out, will cause splashes and trickles of beer as it drains back out. I'd rather lose a little bit of beer in the fermenter to this than splash around the beer in the keg.