How to add post title into the post directly

[OQP]

Hi Friends, I just want that I can post my thread title into the post directly through creating / modifying new thread and not through editing postbit template for example:

https://vborg.vbsupport.ru/showthread.php?t=123337

After installing this mode you can able to add users info anywhere in the form.. like if you post Hi {usename} it will show me Hi OQP
So i just need like this that when i will post {title} is good post it should show I need to get title of the post into the post is a good post

Edit: I have just put this line in my index.php but it is still not working...
1st Try- Not worked

PHP Code:

echo $vbulletin->$thread['preview'] = str_replace("{title}", $thread['threadtitle'], $vbulletin->$thread['preview']); 


2nd Try- Not worked

PHP Code:

if ($vbulletin->$thread['preview'])
{
echo $vbulletin->$thread['preview'] = str_replace("{title}", $thread['threadtitle'], $vbulletin->$thread['preview']);
} 


3rd Try- Not worked

PHP Code:

echo $vbulletin->$thread['preview'] = str_replace("{title}", $post['title'], $vbulletin->$thread['preview']); 


Please help me to get it work....

Thanks in advance... for helping me.

Regards,