InfoPath Dev

I've built a Sharepoint List info path form and am trying to create an auto increment field based on the ID of the list item. I've tried using max() and count() formulas but it only seems to be counting the item it is creating rather than all items in the list. Any help would be much appreciated.

 http://www.wonderlaura.com/Lists/Posts/Post.aspx?ID=137

 

I've used this technique many times works well but requires sharepoint designer.