Add Currently Active Users in forumdispay?

I'm trying to add Currently Active Users in forumdisplay page. this is what I did:

- I added $activeusers in forumdisplay template.
- Then I added:
eval("\$activeusers = \"".gettemplate('forumhome_loggedinuser')."\";" );
from index.php in forumdispaly.php at the bottom.

it didn't work!! what should I do to run this hack?

[JohnM]

you have to copy the whole who's online code from index.php, not just the template display