Make Lion backupd believe all required AFP features are supported by your NAS/AFP server.
Of course, chances are, it actually needs all those features and your data isn't that safe with this hack...

Building (needs XCode 4.x):
git clone git@github.com:msftguy/backupd-afpbits.git
cd backupd-afpbits
git submodule init
git submodule update
open backupd_anyfs.xcworkspace
# now select backupd_anyfs project and click Build.