Filter network and web traffic by Windows User with SonicWall Analyzer

Hi all,

I have a TZ-215 Sonicwall with the following sw:

Firmware Version: SonicOS Enhanced 5.9.0.0-91o
Safemode Version: SafeMode 5.0.4.7
ROM Version: SonicROM 5.0.5.6

I have it licensed for Analyzer and I have recently installed an Analyzer (8.2 version, 64b, 950GB) virtual appliance on an ESXi Server (5.1.0) that we have in the office. 

The thing is I'm able to make quite pretty reports filtering the initiators by IP. But, in our architecture, we have one central virtualized Server (Windows Server 2008 R2), and all the workers connect to this server using thin clients on their desktops. Therefore, all the web traffic generated by them, have the same source IP, this is, the central server's IP.

I wonder if there is a way to differentiate the web traffic based on the Windows User, so we can have reports of the traffic that is being generated in our office sorted by employee and not just the bulk traffic of the central Windows Server.

Thanks in advance!!