Backing up VMware VM's

We are backing up our VM's with BackupExec 2012 up until a month ago the VM backups were running fine using the SAN as the transport.  Now they are wanting to only run over the network.  The only thing that has changed is for some reason the backup server seems to have initialized the luns that the VM's are on.  Is there a way for me to un-initialize these so we can get back to backing up via SAN?

Any help is great.

Thanks