It looks like your comment link is being generated inside of MT with something like:
CODE
<$MTEntryPermalink$>#comments
Your default MT permalinks are pointing to HTML pages. If you want to keep that as a default but also have a XML page listing the comments, it seems like the best thing to do would be to modify the
individual entry feed with comments to only show the comments or something.
On that page, Phil explains how to create an XML page for each entry:
QUOTE
Then, create a new archive template (Templates -> Create new archive template), name it something useful like Individual post RSS feed, paste in the template code above and save the template
Tell MT what sort of archive template it should be (Blog Config -> Archiving -> Add New...): Archive Type should be Individual, and the Template should be the one you just created
Tell MT how to name the new files: in the input area in the Archive File Template by your newly created entry, add <$MTEntryID pad="1"$>.xml so that the filename for your RSS feed for entry 666 (which has a filename like 000666.php or 000666.html) will be 000666.xml
Save your changes, and then Rebuild Individual Archives Only, and you should have RSS feeds for each entry and its comments. If it worked, and adding a new comment rebuilds the feed, you just need to add a link to the feed (in your individual entry template at least, possibly also in the comment popup template), and then sit back and enjoy the increase in comments once people discover that they can keep track of replies
After this, you could create a link to this page such as:
CODE
<$MTBlogArchiveURL$><$MTEntryID pad="1"$>.xml
Put this in place of the link I mentioned at the start of this.