Time Machine Backup to Samba Share under Mac OS Lion

Question

In earlier versions of Mac OS you could enable TimeMachine to use Samba-Shares as a Backup-Target using this:

defaults write com.apple.systempreferences TMShowUnsupportedNetworkVolumes 1

and create a backup image with this script.

Sadly Time Machine now says that my drive does not support the necessary AFP protocol.

Is there a workaround for this?