I think you may have misunderstood how the SSO works. What this does is to allow more than one BE media server to access a shared backup device.
If I understand you correctly, you want to back up the data on your SAN faster. You have (at least) 2 options:
Make each of your SAN-connected servers a media server. Each server then shares the backup device. You need multiple BE licenses for this.
Ensure your BE media server has access to the SAN. Get the Advanced Disk Based Backup Option. Ensure your media server can access filesystem snapshots. Use Off-Host backups. This means that your remote server takes a snapshot of the filesystem, which is then imported and backed by the BE media server.