[Dream]

If you want to add this to the bottom reply button too, find in SHOWTHREAD

<a href="newreply.php?$session[sessionurl]do=newreply&amp;noquote=1&amp;p=$LASTPOSTID" rel="nofollow"><if condition="$show['closethread']"><img src="$stylevar[imgdir_button]/reply.gif" alt="$vbphrase[reply]" border="0" /><else /><img src="$stylevar[imgdir_button]/threadclosed.gif" alt="$vbphrase[closed_thread]" border="0" /></if></a>

and before add

<if condition="$show[closethread] AND $last_reply_alert_phrase"><span class="highlight">$last_reply_alert_phrase</span></if>