I got it!
I managed to get the SB800 to fire remotely, wirelessly, while the on-camera flash did not fire, and I didn’t have to buy any fancy wireless modules or what-not to make it work! Man, I really like this D300.
I set the e3 “Flash cntrl for built-in flash” setting to “commander mode”, set the built-in flash to “–“, set group A to “AA” and then OK. Then, on the SB800 I held the Set button for 3 secs, chose the squiggly line remote setting, and set it to “remote”, then set the flash mode to “A” (or “TTL”, either should work and I’m not sure which one I used). The channels and groups were already the same. I popped up the built-in flash to put the camera in flash mode, then took my shot. As long as the SB800 could see the built-in flash monitor flashes, it would work.
I’m all set for those cool off-center, back-lit nude photo shoots now. Ladies, please form an orderly line … first come, first served.