Windows XP support in NBU 7.6.0.3

Hi, our master server is NBU Enterprise server 7.6.0.3. It is also the media server. There are no other media servers.  We have one Windows XP SP3 32bit client. I checked the NBU SCL and it seems NBU 7.6.0.3 does not support open file backup for Windows XP SP3 32bit. My question is:

1) I am thinking if we can install NBU 6.5 client in the Windows XP machine. Does NBU 7.6.0.3 master server (which is also the media server) support NBU 6.5 client? 

2) If no in 1), are there any workaround so that we can back up open files for Windows XP machine in this case?

Thanks in advance.