Ok, here's how to do it.
Out of the 30 pins on the GoPro bus, there is not one to click the shutter. Go figure. But the GoPro does have a mode that you can set that automatically starts either taking one pic, go into the time lapse mode or video mode when power is applied. In this application I set the GoPro to the time lapse mode. When motion is detected by the SSII power is applied to the GoPro. It instantly goes into the time lapse mode and takes a pic every two seconds for one minute after motion is last detected.
Here is a nice cheat sheet for the GoPro setup.
My original setup had the GoPro in a box with the SSII. It worked ok but for my application I usually like the motion sensor to be separate from the camera so I can use it for other camera setups or easily swap between the different GoPro models. Plus the GoPro already has a nice waterproof housing. My next mod to this setup will be to install the motion detector in an empty GoPro housing and camo both. One other thing I will do in the next iteration is install a photo transistor in the circuit to turn off the setup at night. Or turn it on at night and off for daytime when using the IR modded GoPro.
1 - GoPro Hero HD or Hero 2
1 - Bus break out board from here. http://www.chargeconverter.com/store/index.php?route=product/product&product_id=151
1 - PN2222 NPN Transistor
1 - 10K Resistor
1 - Snapshot Sniper SSII controller or other programmable controller
1 - SPST Switch
1 - Enclosure - I used a Radio Shack enclosure but you can use whatever you want.
1 - A few inches of wire
I used the bus breakout board for ease of experimentation. My final version will have the transistor and resistor in the motion detector box and only have a connector for the bus.
Here is the schematic and a couple pics.
I had never used anything with a Picaxe controller so after a little research I built the circuit below to adjust the timing of the turn on - turn off pulse.