UPB light switch install help

I'm feeling pretty boneheaded, but before I screw something up I'd like to run this by you...

I have 35A00-3 HAI 600W Non-Dimming Switch, install instructions below.

http://www.smarthome.com/manuals/110523.pdf

I'm replacing an existing switch. The only things hooked up are two blacks (load and line) and the ground (copper).

The new switch wants neutral (white). There's a few "whites" bundled in the back of the electrical box, but how do I ensure they're actually neutrals?

And so I'm clear, the line is the hot side of the switch (the hot black), the load is the other ("cold" black).

I know, I should call an electrician, but this can't be that hard.

Thanks,
Shawn

OK - it's continuous to ground. I've got it hooked up, and I can get the blue LED blinking to indicate it's in setup mode, but it a) isn't turning the light on and off, and b) is not being found by the automation controller (HAI OmniPro II).

Any suggestions?