I believe that the port that listens for these "test WBEM" alerts is dynamically chosen at boot. It would make sense that it is actually using WMI under the hood on windows. If you google "wmi ports" you will find more information.
I ran a wireshark capture on my HP SIM server while sending a successful test WBEM event from a client and noticed an initial connection to port 135 and then a longer connection to port 56831.
I then ran 'netstat -anb' from an elevated command prompt and saw that a program named 'wbemcons.exe' was listening on port 56831.
I would suggest to try (temporarily) turning off the firewall on your HP SIM server, or put in a firewall exception for the "C:\Program Files (x86)\The Open Group\WMI Mapper\bin\wbemcons.exe" program. I would not recommend putting in a firewall rule just for the port because it most likely be different each time you boot your system.
