But the problem was I did not have enough storage on the exchange server to recover with a RSG.And adding additional storage was not an option , next step for customer was a hardware upgrade for exch 2010.So luckily enough I had a Hyper-V Server with loads of storage so I did the following.
1. Created a new vm with a 500gb dynamic disk , added in a legacy adapter , 4gb ram , 4 virtual cpus.
2. Then started up the new vm and booted into the free nas os, selected the legacy adapter , set the legacy adapter to receive dhcp, took note of ip address.
3. Then logged into the free nas via the http://ip received from dhcp. User name: admin password:freenas
4.Configured freenas as per this article from Dave Lawlor
5. Then downloaded and installed latest microsoft iscsi initiator for Server 2003.
6. Connected to my freenas via iscsi and formatted my new volume.
7. Then moved my RSG to the new volume I created.
This was an interesting resolution to my problem as I couldnt locate the RSG on anything but a local drive and exchange thought my new volume was a local drive.
Now this problem was probably a once off but it is a really simple way for people to play around with iscsi and san technology and its free.