MSP430F6659: Using a 16Mhz clock for USB BSL

Hello,

I want to use the USB BSL function to download new firmware to the device. My XT2 clock is  16Mhz. The app note says it auto detects 4,8,12 or 24Mhz. Somewhere, I once thought I saw 16Mhz was included, but I can't find that now. The App note SLAA452 says I have to use IAR to modify the code. I use CCS7 for development. For such a simple modification do I really need IAR?  Modifying the BSL documentation is a bit confusing, can you steer me in the right direction?

Thanks,

Jerry