Local HTML still sounds like a good option, to avoid these problems.
Have each command in its own file, sharing a common CSS file.
I think this would also be an acceptable instance where frames would be useful! (to list all the commands on the left)
You should be able to link directly to the selected command in the editor, and still use frames.
Then an online help system would use the same files, and can always be kept up-to-date.
(How about the MAC port? Does it have its own help system?)
But, not a big deal, I'm used to the current system.