Carpentry and Woodworking - Need details on soffit box for shed

I'm planning a 10x12 shed and have some questions about the soffits, particularly in the bottom corner section of roof that overhangs the non-load-bearing wall.

I understand how the sub-facia, facia, soffit, and f-channel goes together along the load-bearing wall. The problem I have is how the soffit box is constructed as the soffit extends under the overhang (the part where the roof sheathing, lookouts, and non-supported roof rafter is).

Is there an illustration or book that describes how to do this? I've looked online and even at some books in some big box hardware stores and have come up empty. Thanks.

-joe

Cut a triangle with the top slope the same as your roof pitch.
Extend the look out ledger to the outside rafter. The triangle covers the end of the ledger.

Check the drawing below. It's not very good, but maybe it will help.

http://preview.kstout4.photosite.com/

Here's a few more photo links to help you picture it.

http://pg.photos.yahoo.com/ph/thexsleeper/detail?.dir=af9d&.dnm=918c.jpg
http://pg.photos.yahoo.com/ph/thexsleeper/detail?.dir=af9d&.dnm=c092.jpg