Help with Template hook location

[Power_user_EX]

Hi , I have created some custom profile fields (field5-7) and I have vb 4.1.11 installed on my forums.
I want to display the custom field data in the signature using templates.

1) I have made a template called "cuz_sig" which is as follows :

            
<vb:if condition="$post['field5']">
  <dt>Field 5:</dt><dd>{vb:raw post.field5}</dd>
</vb:if>
<vb:if condition="$post['field6']">
   <dt>Field6:</dt><dd>{vb:raw post.field6}</dd>
</vb:if>
<vb:if condition="$post['field7']">
    <dt>Field7:</dt><dd>{vb:raw post.field7}</dd>
</vb:if>

2) Made a plugin called "custom_sig" as follows:

PHP Code:

global $template_hook;
$newTemplate = vB_Template::create('cuz_sig');
$template_hook['postbit_signature_end'] .= $newTemplate->render(); 


Product : vBulletin
Hook Location : postbit_display_complete
Active : Yes

I've tried with other postbit hook locations that are available in the drop down , but still not working.

3) PROBLEM : The custom field data doesnt show up! The output is simply blank.

4) If remove the vbif condition tags then output is :

Field5:
Field6:
Field7:

5) Which template hook should I use so that it gets invoked correctly?. It seems that the code has no reference to $post[] or {vb:raw post} bcoz {vb:raw post.fieldx} is returning nothing.

Need some help asap!

-Thanks