I have bridged cpg1.4 with phpbb3 with use post-based groups turned off, however i wanted to allow forum certain forum usergroups administrator access also, so heres what i did...
Edit phpbb3.inc.php and replace
$this->admingroups = array(5);
With:
$moderator_group = array(4);
$administrator_group = array(5);
$this->admingroups = array_merge($moderator_group, $administrator_group);
4 and 5 being moderator and adminstrator forum group codes respectivly.