[Chris M]

Not very

Open root/member.php
Find:

// ############################### start modify options ###############################

Add above:

// ############################### user cant see sigs ###############################
if ($action=="cantseesigs") {
$templatesused = "nosigs";
include("./global.php");
if ($bbuserinfo[usergroupid]!=6) {
show_nopermission();
exit;
} 
if ($bbuserinfo[userid]==0) {
show_nopermission();
}
$DB_site->query("UPDATE user SET showsignatures='0' WHERE userid='$bbuserinfo[userid]'");
$goto="showthread.php?s=&threadid=$threadid";
eval("standardredirect(\"".gettemplate("nosigs")."\",\"$goto\");");
exit;
}

// ############################### user can see sigs ###############################
if ($action=="canseesigs") {
$templatesused = "showsigs";
include("./global.php");
if ($bbuserinfo[usergroupid]!=6) {
show_nopermission();
exit;
} 
if ($bbuserinfo[userid]==0) {
show_nopermission();
}
$DB_site->query("UPDATE user SET showsignatures='1' WHERE userid='$bbuserinfo[userid]'");
$goto="showthread.php?s=&threadid=$threadid";
eval("standardredirect(\"".gettemplate("showsigs")."\",\"$goto\");");
exit;
}

Add to the phpinclude template:

if ($bbuserinfo[usergroupid]==6) {
if ($bbuserinfo[showsignatures]==1) {
$siggies=<a href=\"member.php?s=&action=cantseesigs\">No Signaturess</a>;
}else {
$siggies=<a href=\"member.php?s=&action=canseesigs\">Show Signatures</a>;
}
}

Now edit the postbit template, and add:

$siggies

wherever you want...

Now add 2 templates:
Name: showsigs
Content:

Signatures turned on

Name: nosigs
Content:

Signatures turned off

Satan