General Support: passing variables to plogger

plogger seems great and my main concern is for my vbulletin forum users to be able to use it & comment without having to log in twice. so far i have attached some vb code at the start of the plogger index which checks if they're logged in etc -- and what i'd like to do is simply pass their username to plogger so that the comment form already has their vb username as the author. i tried to simply use the vb variable in plogger's gallery.php but it wouldn't pass it...