This doesn't directly answer your question, but perhaps an alternative solution for your offline backup setup.
Have you looked at JungleDisk and DropBox?
These are fairly inexpensive "cloud" solutions that mount as if they were network drives in Windows/Linux/Mac.
I have been pretty pleased with JungleDisk. I think I have about 20GB backed up and it costs me about $4.50/month with Amazon S3 as the backend.
