I edited the 10.5.7 .kext file, and it most definitely works so far.
Note: in the System/Library folder, under the Extensions folder, you will see an "Extensions.mkext". This is a kernel extensions cache. Everytime you modify the Extensions Folder, you will see this file get overwritten. I noticed last time that going into the .kext file and making a change was not enough - you had to envoke a modification to the .mkext, or after a couple reboots, the gestures get read from the cache, which still contain the old .kext.
I'm guessing. But mine is working, using the 10.5.7 .kext.