Just had a situation where I ghosted then virtualized a Windows SBS2003 server once it was on VMWare I installed SBS2003 Service Pack 1 and all the patches required for a SBS2011 upgrade.

Unseen by me this appears to have updated the Domain firewall Policy and turned on all the Connecting Client Windows XP Pro SP3 firewalls.

Instead of turning the Windows Firewall off.  I've been busy adding exceptions to the "Small Business Server Windows Firewall" Group Policy under Computer Configuration ==> Administrative Templates ==> Network ==> Network Connection ==> Windows Firewall ==> Domain Profile

Windows Firewall: Define Program Exceptions

%windir%\system32\wbem\unsecapp.exe:LocalSubnet,10.2.0.0/24,10.11.11.0/24,172.16.10.0/24:enabled:UNSECAPP

Windows Firewall: Define Port Exceptions
10000:TCP:LocalSubNet,10.2.0.0/24,10.11.11.0/24,172.16.10.0/24:enabled:Backup Exec Agent for Windows
6101:TCP:LocalSubNet,10.2.0.0/24,10.11.11.0/24,172.16.10.0/24:enabled:Backup Exec Browser Service
5800:TCP:LocalSubNet,10.2.0.0/24,10.11.11.0/24,172.16.10.0/24:enabled:VNC HTTP Access
5900:TCP:LocalSubNet,10.2.0.0/24,10.11.11.0/24,172.16.10.0/24:enabled:VNC Viewer Access

I have added the above to the Group Policy

Then run gpupdate /force on the clients or reboot

To test WMI (taken from the Spiceworks Forums)

wmic /user:USER_NAME /password:USER_PASSWORD /node:IPADDRESS systemenclosure get serialnumber

USER_NAME = the domain account, SSH account or SNMP name entered in Spiceworks

USER_PASSWORD = the password for the above account

IPADDRESS = ip address of the unknown device