Who knows what to do in drupal 7? Thanks in advance))

Yes, You need to simple override the theme function "function theme_heartbeat_comment".
You will need to take over the function and replace this line beneath with your realname implementation (I checked realname for you, and think the sollution, included in the code beneath as well)

// Change this
 $output .= l($account->name, 'user/' . $comment->uid) . ' ';
// Into this
$output .= l(realname_make_name($account), 'user/' . $comment->uid) . ' ';

Glad i can refer to this issue now. I will spontanuously create a documentation page on
http://heartbeat.menhireffect.be/docs/using-realname-module

Sorry to reopen this. Could you explain where and how is to be copied that piece of code?

thanks!

It is explained on that page. Its a theme override for theme_heartbeat_comment. So just the basic drupal theme implemenation.
phptemplate_heartbeat_comment in your module or theme's template.php will fix your problem. That is what theme functions are for.

Sorry to say that that page didn't say where to place the code, although a user with knowledge in theme functions may have already known that because it seems obvious. It is not my case. That's why I made a dummy question, but I really needed it.

Thank you anyway for your explanations, I know now where to place that code and future theme functions.

Who knows what to do in drupal 7? Thanks in advance))