[miz]

its weird you got only the function and not the bbcode this both supuse to be on the same php script

here is the bbcode addon :
open includes/functions_bbcodeparse.php

	// [HIGHLIGHT]
	$bbcodes['custom']['find']['[highlight]'] = '#\[highlight\](.*)\[/highlight\]#esiU';
	$bbcodes['custom']['replace']['[highlight]'] = "handle_bbcode_parameter('\\1', '" . str_replace("'", "\'", '<span class="highlight">\1</span>') . "')";
	$bbcodes['custom']['recurse']['highlight'][0] = array('replace_html' => "<span class=\"highlight\">\\7</span>");

below that add :

	// [HIDE]
	$bbcodes['custom']['find']['[hide]'] = '#\[hide\](<br>|<br />|\r\n|\n|\r)??(.*)(<br>|<br />|\r\n|\n|\r)??\[/hide\]#esiU';
	$bbcodes['custom']['replace']['[hide]'] = "handle_bbcode_hide('\\2')";
	$bbcodes['custom']['recurse']['hide'][0] = array('handler' => 'handle_bbcode_hide');

and thats all - bbcode added
but you need to add function on this page, thats why im not sure your hack is working