Good to see 3.1 is working for 32bit, for 64bit I doubt it would. I've had to use virtual pc and xp mode to get Max 5 to work on Windows 7 64bit in the past.
Windows 7 Professional and Ultimate both allow free download and installation of what is called XP Mode which is virtual pc with XP loaded and you don't need any cds or license keys. For all version of Windows Virtual PC is available and you can load XP or 98 or whatever OS you like on it, you just need the disk and key for the os. Neither of them support Direct 3d so you wouldn't be able to launch BC. Max 5 works on XP Mode, so I would expect 3.1 to as well.
I would expect genty's instructions to grab the proper registry keys would make it seem installed properly, which might let your exporter work, so long as you don't require launching BC at any point. Just have a properly installed BC with the SDK already initialized on another pc and copy the entire folder (and get the registry keys) to the virtual pc drive to the same path. The registry keys will likely point to the folder so it will most likely need to be the same "location" and name on the virtual pc.
Another option if your using 64bit would be a dual boot setup with XP.