If its not in the MENU then you will have to add it in via the programming software.
You could run into a problem once your cable comes in. To put the radio into PROGRAMMING MODE hold all 3 buttons on the side. The side buttons and the PTT. Hold all 3 and turn the radio on and the screen should go all pixle like. Then you can try and read it with the software.
If you get an error when you try and read the radio with Programmer. Then your kinda screwed for doing things yourself. You will have to either spend big $$ and buy Hariss RPM to program the radio, or send it to someone who has RPM.
BUT! If your cable to read the radio fine with Programer. Go to the OPTIONS tab in programmer. Scroll down and click PROGRAMMABLE MENUS. Then you can select FEATURES from the drop down menu
Is there a menu called REVISION enabled in the radio currently? If so. Post the info from there, that can tell us if it was programmed with RPM or Programmer