Win2K8 backs up twice

Hi,

We recently setup our first Win 2008 server in Avamar (server 5.0).   It seems to be  running one  backup each  for  the Windows File System  Plugin

AND  the VSS  plugin.    We do have both plugins listed in the dataset,  which is a Windows-specific dataset that  includes  those 2 plugins  ONLY.

In the datsets  for all our Windows  machines,  I've  always included both VSS and Windows Filesystem plugins,  and have yet to see any other machine back up twice,  (one for each plugin)  until this  2K8  box came along.     Now looking back at the Activity Monitors,  it  doesnt  look like any of the previous backups used  the  VSS plugin at all.  (Until now,  Win 2K8)...    (OK ...why then did I have VSS in the  dataset???    I'm not a Windows admin... but it seems that the previous windows  backups  were  running  VSS  snaps  prior  to avtar's  work.  I thought  I needed the VSS plugin... but  I guess not... So when is the VSS plugin used??)

Has  anyone  seen this  Avamar behavior  with  Win 2008 Server?    Should  I just remove  VSS  altogether  from  all the  datasets? ... and  why does  2K8  handle this  any differently. 

Any insight  is  appreciated,

Thx,

Dave