The forum integration is only CSS integration. Looking at your header they look different cause you have different html. Still is up to the customer to put whatever html they want around photopost to make it look more like their forum.
As an example you want to add this at the top of your header of what you have already in reviewpost etc
<table class="bodyline" width="100%" cellspacing="0" cellpadding="0" border="0">
and in your footer at the end of reviewpost