Parse BBcode in postbit (3.6.5)

[gen.Scorpio]

find the solution for custom profile fields:

if ($userinfo['field5'])
{
if (!is_object($bbcode_parser))
{
    require_once(DIR . '/includes/class_bbcode.php');
    $bbcode_parser =& new vB_BbCodeParser($vbulletin, fetch_tag_list());
}
$userinfo['field5'] = $bbcode_parser->do_parse($userinfo['field5'],true, true);
}

but now, have a new problem:

with that code u can parse bb in the profile page. it works.
now let's see about the post. when i click to a user with a field5 with bb code, i still see no parsing.

so im trying to create a new plugin, based on this work:
Custom Rank Image for each User HACK
------------------------------------
version 1.0 (beta)
by Marris
January 14, 2006
for vBulletin 3.5.3

i create a new plugin, the hook is
postbit_display_complete

if ($post['field5'])
{
if (!is_object($bbcode_parser))
{
    require_once(DIR . '/includes/class_bbcode.php');
    $bbcode_parser =& new vB_BbCodeParser($vbulletin, fetch_tag_list());
}
$post['field5'] = $bbcode_parser->do_parse($post['field5'],true, true);
}

if activate the plugin, the post of a user with a field5 with bb code simply goes blank, the page dont load.


=============The old post
im getting crazy!
using 3.6.5
i tried these ways:
first

if (!is_object($bbcode_parser))
	{
	    require_once(DIR . '/includes/class_bbcode.php');
	    $bbcode_parser =& new vB_BbCodeParser($vbulletin, fetch_tag_list());
	}
 	$profilefield['value'] = $bbcode_parser->do_parse($userinfo["$profilefieldname"],true, true);

second

$profilefield['value'] = $bbcode_parser->do_parse($userinfo["$profilefieldname"],true, true);

the hook is always member_customfields

then i created my space (field5) in the profile....

results: i see the field5 box, the text in it... but it DOESN'T PARSE!
i still see the tag [u] [img] or whatever bb code...

where i make the error?

thanks in advance - im noob on vb! -