I would get this:
http://www4.sprint.com/pcsbusiness/d...0_WWE_Ship.exe
Once you have it you can unzip the .exe (I use winrar and it works well) into a directory of your choosing. Once the exe is unziped go to the Outputfile directory and grab radio._nbf and put it in the same directory as the colonel 3.5 ROM.
From there you just follow the normal flash procedures that colonel posted. Having the radio._nbf will cause the phone to upgrade the radio after the CE rom is flashed.
Be advised, if you keep it there, it will update the radio every time you flash so if you dont want to do this (why would you), I suggest moving the file out of there once you have updated the radio.....
Hope this helps.