How to program 2nd curtain

Hi Everyone, I just got my d600 back from Nikon repair center for the 3rd time and I always have to go in and re-customize everything for my sensibility. I use 2nd curtain as my norm for flash, and I thought all I had to do was press and hold the flash button while turning the back command dial, right? Nothing happens. The front command dial properly changes the intensity (I prefer -7) so that works. Any thoughts? I feel like I'm just making a stupid mistake.
Thanks for your help.

Try the manual.

Just pulled out my manual. Seems I'm doing it right. I have it in M mode so it should work. I always did before. #@*$.

Save your settings on a memory card, then transfer that file to your computer. So if you ever want to reset the camera to those settings, you simply do a 2-button reset, then reinstall your settings.

Weird. This morning it works just fine......huh?

Keoki...fill out the rest of your profile, OK? It's lacking in a few areas.

Ok Jack. Done : )

By the way, does backing up the settings to a file back up absolutely everything or?