Ryan,
I really wouldn't expect you'd need to jump through hoops to get this working, but I just tried enabling the boot agent on mine and using CTRL+S...no joy. So you're not alone. I'll do some more searching and if I can't find anything useful I'll see if I can find someone in the know tomorrow.
I'd be interested to know if CTRL+S works when it's plugged in with an Ethernet cable.
Jason