Can anyone advise me if there are any issues if a Truecrypt encrypted container is created on a WDMB II NAS.

Also, where can I get further information on encrpyting backups to the NAS using the Anywhere Backup software. 

I am using the NAS in RAID 1 configuration

I’ve never heard of it being used on the NAS, but I can’t see why it wouldn’t work. WDAB does have basic encryption built in, but if you are serious about security I would use something more sophisticated.