Backup to external hardrive that is setup as a network share

I have Backup Exec 2012 running on a Windows Server 2008 R2 SP1 server.  I have connected an 3 TB external hard drive to a remote server at a different location and set that drive up as a network share.  That server is also Windows 2008 R2 SP1 and is running the symantec backup agent for windows.  I have been able to successfully run a backup job of that remote server to the network share that is local to that server.  My problem is the speed of that backup.  I was hoping since the drive was local to the server it was backing up, I would get speeds similar to what I get with other servers that are on the same subnet as the server (around 380 Mb/minute).  Instead I am getting around 15 Mb/min.  Does anyone have any thoughts or suggestions?  Thanks