Hi,
While the ESO license is correct, having 4 x RAWS agents won't work. BE needs to be installed on those servers that need to access the FC-attached tape library. Since this is a full installation of BE, you'd need that number of licenses for the number of servers you want to backup directly across the SAN.
Your best bet for reference is on the TN below:
http://www.symantec.com/docs/HOWTO24287
For confirming the licensing requirements, you can contact the SYmantec licensing department. But the TN above states that SAN SSO is for multiple media servers to connect to a shared device.
Thanks!