Show Disqus form under old comments

greetings
I have a site with comments on, and I migrate to Disqus: the problem is that i can't import old comment inside disqus (import feature do not work) and I can't show disqus form at the bottom of old comments.
Is there anyway to show disqus form and comments at the bottom of old comments?
[I tried to put some code inside comment.tpl but it shows only the first comment, then disqus form and then the rest of other comments]