Thank you for sharing with us your experience.
I successfully managed to edit the Lion kexts without issue, once I had the correct locations provided by the script. The card now works perfectly in both SL and Lion. As for running the script, I have Lion installed on another drive in this machine, so I simply modified the script itself to look on the Lion drive for the kexts and then ran it as normal from Snow Then I modified the Lion kexts from within Snow, rebooted into Lion et voila
Modding the script to point to your Lion installation is relatively easy, if you look at the script you'll see the paths defined in a number of places, just change them all to point to the correct location. For example by default the script has '/System/Library/Extensions' defined as the kext path, I changed that to '/Volumes/OSX/System/Library/Extensions'. Obviously change '/OSX/' to the name of the Lion volume on your machine.
Hope that helps
I will try as per your method.
Will share result with rest.
I hope you don't mind me asking questions if I face any problem.