I have seen a good hack to get around this problem.

At the end of the article add a link "Discuss this on Hacker News" linking to your submission of the article here. Then you can just tweet your article directly and all the HN'ers will click through and comment and vote for your submission. It's not ideal but it works.

One problem is old comments. Anyone that sees the article and wants to add to the discussion is pretty much screwed if it's been more than half a day. HN submissions older than that get few views and fewer responses to any late additions.