Is your san client up in your exchange boxes? If backups are going across the lan is because u cannot reach the pipes on the media servers and this can be because the ft medias pipes, here is one of my nites about this:
NBU-6-ERR-PRO-SAN Client Troubleshooting
#Check PBX on the SAN client
Bpclntcmd -get_pbx_port []
#Confirm is the box is configure has SAN Client
Bpclntcmd -sanclient
#Log SAN Client
Vxlogview -i 200 -o 200
#Check FT Media bus Speeds
Vxlogview -i 199 -o 199 | grep InitializeSDC
#Check for Orphan Pipes on NBRB
Nbrbutil -listOrphanedPipesnbrbutil
Nbrbutil -releaseOrphanedPipes
#Check FT Media configs and List SAN Clientsnbftconfig -listactive [-C -verbose]nbftconfig -listtargetsnbftconfig -[lc]listclients -C [-verbose]nbftconfig -listclients -Me nbftconfig -rescanclient nbftconfig -getconfig