Need assistance with the Bimmer app please

Hey guys. I just recently got an iPhone 4 and downloaded the Bimmer app. I can read the threads and posts without any difficulty. However, I cannot figure out how to post a reply. When I open a thread and want to post a reply, the only options that I see on the screen are the “back” button in the upper left corner which takes me back to the list of topics and the symbol in the upper right corner with a square and arrow in it. When I press that, I get options of “open in safari”, “share” and “refresh”, but no way to post a reply.

Can someone teach this old dog a new trick?