I wonder if you could fool the system?
Use web.config to specify that xxx.hta is actually processed via the page xxx.asp??
From the browser's point of view, it would still be seen as ".hta".
I've never mucked with HTA so can't help you with that, per se.
An optimist sees the glass as half full.
A pessimist sees the glass as half empty.
A realist drinks it no matter how much there is.