Comment on WordPress Hacks by SEO Dave.
So if it is possible you’d have to use different code than the standard WordPress code I’ve used.
I tried a subscribe to comments type plugin not long ago (tested on another site), but when comments got past page one on a threaded comment page it broke! So it was OK as long as the page didn’t have more than one page of comments :-)
I would like to use a subscribe to comments plugin as well, so if you use one that works let me know and I’ll set it up.