vb.org Archive - Question about using the template hooks

I was updating to the latest version and all went quickly as I have all code mods as plugins. But I still had to fix modded templates one by one. I noticed the template_hooks and thought I might be able to save myself some time in the future by using some of these. So I decided I could try this out on my postbit_legacy template where I have this code at the end to display an ad after the first post:

HTML Code:

<if condition="!$GLOBALS['FIRSTPOSTID']">

 <br>

<table id="post$post[postid]" class="tborder" cellpadding="$stylevar[cellpadding]" cellspacing="0" border="0" width="100%" align="center">

<tr>

    <td class="thead" style="font-weight:normal; border: $stylevar[cellspacing]px solid $stylevar[tborder_bgcolor]" colspan="2">        

        Sponsored Links

    </td>

</tr>

<tr>

    <td class="alt2" style="border: $stylevar[cellspacing]px solid $stylevar[tborder_bgcolor]; border-top: 0px">

<Ad code goes here>

    </td>

</tr>

</table> 

</if>

I figured I could use the $template_hook[postbit_end] hook to do this. I took the code above and put it into a template called custom_postbit_ad_at_end and created this plugin:

Code:

eval('$template_hook[postbit_end] .= " ' . fetch_template('custom_postbit_ad_at_end') . '";');

I didn't know what hook location to use so I've tried everything from global_start to showthread_start to ???

My problem is that it shows the ad after every post, not just the first. So I'm guessing that my conditional is coming up TRUE every time because $GLOBALS['FIRSTPOSTID'] is empty every time. Can somebody throw me a clue as to what I'm doing wrong? Is there a way to make this work? Seemed like it should be simple, but....

Thanks

X vBulletin 3.8.12 by vBS Debug Information
Template Usage: (1)ad_footer_end (1)ad_footer_start (1)ad_header_end (1)ad_header_logo (1)ad_navbar_below (1)bbcode_code_printable (1)bbcode_html_printable (1)footer (1)gobutton (1)header (1)headinclude (6)option (1)post_thanks_navbar_search (1)printthread (1)printthreadbit (1)spacer_close (1)spacer_open Phrase Groups Available: global postbit showthread	Included Files: ./printthread.php ./global.php ./includes/init.php ./includes/class_core.php ./includes/config.php ./includes/functions.php ./includes/class_hook.php ./includes/modsystem_functions.php ./includes/class_bbcode_alt.php ./includes/class_bbcode.php ./includes/functions_bigthree.php Hooks Called: init_startup init_startup_session_setup_start init_startup_session_setup_complete cache_permissions fetch_threadinfo_query fetch_threadinfo fetch_foruminfo style_fetch cache_templates global_start parse_templates global_setup_complete printthread_start bbcode_fetch_tags bbcode_create bbcode_parse_start bbcode_parse_complete_precache bbcode_parse_complete printthread_post printthread_complete
Messages:

X vBulletin 3.8.12 by vBS Debug Information

Page Generation 0.01122 seconds
Memory Usage 1,710KB
Queries Executed 10 (?)

More Information

Template Usage:

(1)ad_footer_end
(1)ad_footer_start
(1)ad_header_end
(1)ad_header_logo
(1)ad_navbar_below
(1)bbcode_code_printable
(1)bbcode_html_printable
(1)footer
(1)gobutton
(1)header
(1)headinclude
(6)option
(1)post_thanks_navbar_search
(1)printthread
(1)printthreadbit
(1)spacer_close
(1)spacer_open

Phrase Groups Available:

global
postbit
showthread

Included Files:

./printthread.php
./global.php
./includes/init.php
./includes/class_core.php
./includes/config.php
./includes/functions.php
./includes/class_hook.php
./includes/modsystem_functions.php
./includes/class_bbcode_alt.php
./includes/class_bbcode.php
./includes/functions_bigthree.php

Hooks Called:

init_startup
init_startup_session_setup_start
init_startup_session_setup_complete
cache_permissions
fetch_threadinfo_query
fetch_threadinfo
fetch_foruminfo
style_fetch
cache_templates
global_start
parse_templates
global_setup_complete
printthread_start
bbcode_fetch_tags
bbcode_create
bbcode_parse_start
bbcode_parse_complete_precache
bbcode_parse_complete
printthread_post
printthread_complete

Messages:

X vBulletin 3.8.12 by vBS Debug Information
Page Generation 0.01122 seconds Memory Usage 1,710KB Queries Executed 10 (?)
More Information
Template Usage: (1)ad_footer_end (1)ad_footer_start (1)ad_header_end (1)ad_header_logo (1)ad_navbar_below (1)bbcode_code_printable (1)bbcode_html_printable (1)footer (1)gobutton (1)header (1)headinclude (6)option (1)post_thanks_navbar_search (1)printthread (1)printthreadbit (1)spacer_close (1)spacer_open Phrase Groups Available: global postbit showthread	Included Files: ./printthread.php ./global.php ./includes/init.php ./includes/class_core.php ./includes/config.php ./includes/functions.php ./includes/class_hook.php ./includes/modsystem_functions.php ./includes/class_bbcode_alt.php ./includes/class_bbcode.php ./includes/functions_bigthree.php Hooks Called: init_startup init_startup_session_setup_start init_startup_session_setup_complete cache_permissions fetch_threadinfo_query fetch_threadinfo fetch_foruminfo style_fetch cache_templates global_start parse_templates global_setup_complete printthread_start bbcode_fetch_tags bbcode_create bbcode_parse_start bbcode_parse_complete_precache bbcode_parse_complete printthread_post printthread_complete
Messages: