I'm pretty sure you would just find the coding that dispays it, and put that conditional around it. Go into your ftp and find the name of the rep icon, and then do a search for the name of the icon. Then find where it displays the image source and everything, and condtionalize it.. Is conditionalize a word?
EDIT: I went and got mine:
Code:
<if condition="$show['reputationlink']"><a href="reputation.php?$session[sessionurl]p=$post[postid]" rel="nofollow"><img class="inlineimg" src="$stylevar[imgdir_button]/reputation.gif" border="0" alt="<phrase 1="$post[username]">$vbphrase[add_to_xs_reputation]</phrase>" /></a></if>