more specific...
http://forums.vwvortex.com/showthread.php?3604801-DIY-hi-line-cluster&p=44436992&viewfull=1#post44436992
hopefully it applies to your cluster? as in, vag-com can do this for your specific cluster..
The clusters can be reprogrammed as mentioned. But before you switch it I'd make sure it's not the fuel pump sender.
There are a few places online that can reprogram the mileage and match the new cluster to your ECU, however you have to send them both the old and new cluster. They have cracked the encryption and dump the EEPROM, then change it manually.
Have you considered disassembling the old cluster and swapping out the stepper motor for the fuel gauge?
I tested the fuel gauge with vag-com the needle moves from empty to full, would it still be the stepper motor?