'The RPC server is unavailable' when converting a physical ISA/Forefront TMG machine to virtual (P2V) in SCVMM

When I try to convert a physical ISA/TMG machine to virtual using SCVMM, i keep getting an error in the Collect machine configuration step ('Scan Now' button):

VMM is unable to complete the request. The connection to the agent MACHINE_NAME was lost.

Ensure that the computer MACHINE_NAME exists on the network, WMI service and the agent are installed and running and that a firewall is not blocking HTTP and WMI traffic.

ID: 3157 Details: The RPC server is unavailable (0x800706BA)

Firewall rules allow for RPC traffic from the SCVMM machine to ISA/TMG machine.

Cause: the ISA/TMG server is still blocking specific RPC/WMI traffic, which is not visible when logging the incoming traffic on the server

Resolution:

1. Make sure that you have an appropriate Firewall Policy rule that will allow for RPC traffic from SCVMM to TMG server
2. Right-click on the said rule, click "Configure RPC protocol"
3. Uncheck "Enforce strict RPC compliance"
4. From the right-side menu, click Tasks, then Edit System Policy
5. Under "Remote Management" group, select "Microsoft Management Console (MMC)"
6. Uncheck "Enable this configuration group"

The physical-to-virtual process for an ISA/TMG machine will now resume normally. Undo the changes on the virtual TMG machine after the P2V process is complete.