Dormer face construction

I'm designing a fairly standard dormer extension - all planned and approved, and I've been looking at how it will lay down on its sole plate over the existing wall plate / first floor floor joists (its an existing room in a bungalow with a gable end roof which I'm pushing out to the side. I'm looking at whether the sole plate can lay down on the floor joists but wondering if I should build up - in masonry or wood - between the joists to give extra support. (The joists/wall plate lay on two courses of brick, which close the cavity.) I've got a good BCO but I want to get some info before I discuss it with him.
I've been looking at various sites, and found this one http://www.confidex.co.uk/lc7.html - can anyone tell me what the 'boxes' are, whether this is a standard term (can't find much on Tinternet other than porn sites ...), and if they're for bridging over the existing floor joists as alluded to above. Any help would be appreciated!

i take it, the front face of the dormer is flush with the inside wall and not set back up the roof?

if you fix a sole plate directly onto the joists then align the uprights so that they are directly over each joist, then i can't see a problem.

don't know if this helps?http://daveosborne.com/newsletters/images/gableframe2.gif

yes, noseall the front face will be flush as you say; I agree with you about the sole plate and relative positions of the studs. Thanks very much