How to model metal building gutter/gable trim?

Most metal building manufacturers use a matching gutter and gable trim profile, so that the gutter along the low eave will turn the corner and match up with the profile of the trim running up along the gable rake edge. I'd like to model this so it looks correct, but the problem is that the gutter projects out 5 - 8 inches from the wall, while the gable trim only projects 2 inches or so. I have tried making a generic profile and using it as both gable fascia and gutter, and changing the horizontal offset of the fascia so it moves back into the wall. The corners will not miter correctly. I have tried projecting the roof out a few inches along the low eave, placing a single fascia that turns the corner, then changing the horizontal offset of the whole run. It turns the corner and miters fine initially, but then breaks when I change the horizontal offset to anything other than zero. I have tried moving the gable edge of the roof back a few inches, but that doesn't work because my wall ...  more