Forum Restrict Access After a Post Has Been Made?
 

Is there a permission that allows you to restrict posting to a forum only after someone submits the post?

Currently I have a forum setup to not allow posts by certain usergroups. Those usergroups then do not see the Reply to Post buttons. I would like them to be able to see the Reply to Post buttons but after submitting the post display a message that they don't have permission to post with a link to the Paid Subscriptions page.

I know this is possible as this site is doing exactly that:
http://www.firearmstalk.com/forums/f...iveaway-75715/

I'm just not sure if its a vbulletin setting or a mod.