In case anyone is still following this thread, the renaming 
of the asp links to html links was easier than I expected.  
Using the correct settings, HTTracker provides a line in 
each html file, listing how the file was "Mirrored" - that 
is, the original file name and the name under which it was 
saved.  The user can grep for all "Mirrored" lines and send 
them to a file.  A shell script can then be written to use 
that file to "sed" all of the links in the html files.  
Make sure that you back up your mirror first - I trashed 
mine repeatedly until I got the shell scripts right!

Cheers.