XF 2.0 Ads under first post only

I have been using this to place the ads between first post and second post for 1.xx

<xen:if is="{$post.position} % {$xenOptions.messagesPerPage} == 0 AND {$thread.reply_count} > 0">
Ads code here

Using this ads wont appear below rest of the posts but this does not work with 2.0 for some reason.

Can some one tell me what needs changing to show ads only under the first post and not below ever single post.
I tried using this :
<xf:if is="{$post.position} % {$xf.options.messagesPerPage} == 0 AND {$thread.reply_count} > 0">
ads code here

Page doesn't give any errors with this code but ads block does not show up atall. When I remove the if conditions, ads show up below ever single post.

This is causing a loss of revenue for me and I would highly appreciate if someone can help me with this.