Using that thread as an example, this is from the template "forumhome_forumbit_level1_nopost" (around the sixth line):
HTML Code:
<td class="tcat" colspan="<if condition="$vboptions[showmoderatorcolumn]">6<else />5</if>">
<if condition="$childforumbits">
<a style="float:$stylevar[right]" href="#top" onclick="return toggle_collapse('forumbit_$forumid')"><img id="collapseimg_forumbit_$forumid" src="$stylevar[imgdir_button]/collapse_tcat{$collapseimg_forumid}.gif" alt="" border="0" /></a>
</if>
<a href="forumdisplay.php?$session[sessionurl]f=$forum[forumid]">$forum[title]</a>
I *think* you could add a style to the td tag like this:
HTML Code:
<if condition="in_array($forum['forumid'], array(X,Y,Z))">
<td class="tcat" colspan="<if condition="$vboptions[showmoderatorcolumn]">6<else />5</if>" style="background: url(/images/folder/background$forum[forumid].gif)
repeat-x;">
<else />
<td class="tcat" colspan="<if condition="$vboptions[showmoderatorcolumn]">6<else />5</if>">
</if>
If that doesn't work, then I would add at the top of the template:
HTML Code:
<style type="text/css">
td.cat$forum[forumid] {background: url(/images/folder/background$forum[forumid].gif repeat-x;}
</style>
And then for the td tag (along with the conditional from above):
HTML Code:
<td class="tcat cat$forum[forumid]" colspan="<if condition="$vboptions[showmoderatorcolumn]">6<else />5</if>" >
And, again I'll say you may have to play with it as I'm a trial and error coder.