I could be mistaken, but I don't believe Blackbox handles bindings directly. I think it uses something called bbkeys... I use xmodmap to perform my bindings.
If bbconf isn't already installed (
http://bbconf.sourceforge.net/), try it out and see if it does what you need. I've never used xmodmap to simulate a mouse button, but it might be possible. I know how to bind a combination of a keyboard key and a mouse button to a certain action, but the action wouldn't be context sensitive.
If you're into patching, then this might be the solution for you. It modifies the source code for your specific purpose:
http://blackboxwm.sourceforge.net/Bl...eMouseBindings
From the name, I'd guess Slackintosh is based on Slackware, and that patching and compiling from source aren't foreign to you. I hope I've been of help; I'm experienced with Fluxbox, but I'm very limited in my knowledge of Macs and one-button mice. Good luck with your endeavor.