I always use this procedure:
Change the following registry entries in:
HKEY_LOCAL_MACHINE\SOFTWARE\HTC\ATDbgLog
Enable: 1
LogMode: 1
* Wait a about 10 minutes (more time will not hurt), and soft-reset.
* Check to see that the file \Atlog\ATDbg0.txt has been created.
* Return the values back to what they were (most likely 0) waiting the same amount of time as above.
* Look in the ATDbg0.txt file and you should see a log of commands sent to the CDMA radio and there should be something like this somewhere in the file:
~~~~~~~~~~~SNIP~~~~~~~~~~~~
00:00:00 Tx:AT+HTC_RMSL=0\r
00:00:00 Rx:+HTC_RMSL: (###THIS WILL BE THE MSL###)\r\n0\r
00:00:00 Tx:AT+HTC_ROTKSL=0\r
00:00:00 Rx:+HTC_ROTKSL: 123456\r\n0\r
~~~~~~~~~~~SNIP~~~~~~~~~~~~
The numbers next to the Rx: +HTC_RMSL line should be your MSL
I've used this one too and have had good luck:
http://forum.ppcgeeks.com/showthread.php?t=43560