In the plugin listed above, why not just throw the if into it, so it will be global?
Make:
PHP Code:
$Position = '<!-- / nav buttons bar -->';
$vbulletin->templatecache['navbar'] = str_replace($Position, $Position . '<br /> $Shoutbox', $vbulletin->templatecache['navbar']);
To This:
PHP Code:
$Position = '<!-- / nav buttons bar -->';
$vbulletin->templatecache['navbar'] = str_replace($Position, $Position . '<br /> <if condition="$show['member']">$Shoutbox</if>', $vbulletin->templatecache['navbar']);