Hi Graham,
We're a bit behind on documentation - in JBS 7.0.x there are two new views: messages and media files edit. These are for the front end entry. You add them just as you would add a front end menu item. You set access to the menu from the Joomla menu manager (when you create the menu item). Messages is for study entry, and media files are for, well, media files

. In the edit of the media files there is a link to the Joomla media manager. That's how we are uploading files from the front end now. There will be an upload link at the upper left.
That having been said - there is a bug in Joomla that breaks this. You'll get a Not Authorized error. It is apparently fixed and I hope comes out in 1.6.5. For now - you aren't able to upload from the front end. Sorry about that!
Tom