Backing up Remote Clustered Server

Hi all,

I have the current future planned scenario:

2 file servers in HQ plus one Fiber Attached SAN and 1 LTO 7 Robotic Library

1 file server in remote Datacenter plus one Fiber Attached SAN

2 200MB fiber connecting HQ and Datacenter

Veritas Backup Exec installed on a 4th server in the HQ

All three servers will be a DFSR based cluster

Now, in the scenario that both file servers fail in the HQ and I'm forced in to working from the file server and storage in the Datacenter, what would be the best way for backup exec to still carry on backing up the remote data?

Unfortunately I can't purchase any more equipment due to the budget! Any help on this scenario would be greatly appreciated!

Thanks!