I found this method on a site a while back and used this to get my MSL from my TELUS Diamond as GetSPC and many other methods would not work. I'm assuming it will work for Sprint Diamond as it was originally intended to work with Sprint Mogul.
Change the following registry entries in:
HKEY_LOCAL_MACHINE\SOFTWARE\HTC\ATDbgLog
Enable: 1
LogMode: 1
Wait a reasonable amount of time and soft-reset (I have noticed that it seems to take longer for this value to take affect, so if you reboot and the registry values are not changed, then you need to do it again and wait longer)
Check to see that the file \Temp\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:
Code:
Tx:AT+HTC_RMSL=0\r
Rx:+HTC_RMSL: 354201\r\n0\r
Tx:AT+HTC_ROTKSL=0\r
Rx:+HTC_ROTKSL: 216112\r\n0\r
The numbers next to the Rx: +HTC_RMSL line should be your MSL. You may see a couple of different instances of this number within the text file - try one, if it doesn't work, try the next. The file ATDbg0.txt will either be in \temp or \ATDbg.
Hope this works for you.