Network Backup Software

I've recently switched to a MBP after years using Windows/Linux. Everything has worked great so far and now I'm looking for a good backup solution. My requirements are:

• Supports FileVault (no logouts etc, unencrypted backups are fine)
• Compatible with the Western Digital MyBook World 1TB NAS
• Will work over a Wi-Fi link
• Offers versioning
• 'Set and forget'
• Ideally free.

Time Machine sounded ideal but seems to have issues with FileVault (if I wasn't on the same network as the NAS the logout process took >15 minutes, presumably whilst it looked for it).

I'm currently using the bundled Memeo Backup software. It works okay except it doesn't have any way to delete old files from the backup and is rapidly consuming space on the NAS.

Any suggestions on a good backup solution?

Thanks

 

I used to use grsync on Ubuntu. I'm looking for something thats a little more automated for Mac. That means that versioning is essential (e.g. in case of corrupt files automatically overwriting the good ones in the backup).

I had a look at that. Seems like it could be good. The lack of versioning might be a problem though. How does it react if a backup is scheduled but i'm not on the network?