explain please.

You are now trying to put the link in the posttext itself. Why not just put the link somewhere in the postbit when displaying the post (when you display it, you already have the postid).

Otherwise the best would be to first create the post, retrieve the postid of the created post, then edit the posttext.

I understand, kind've how the signature is already in the template.

Is there a conditional for threadid?
Something like...
<if condition="$threadid == 2">Links here</if>

Use $post[threadid]

Thanks, I got it now.