Hi Duke - currently 1-rail sweep will not do the mitered corners that I think you're looking for there. It is something that I expect to be adding in later on in v2 though.

Check out here for an alternate approach for now:
http://moi3d.com/forum/index.php?webtag=MOI&msg=428.12

- Michael

Offset the centerline of your sweep to the inside (so there are 2 lines). Then use those 2 rails for the sweep to get mitered corners.

Yes this one has urk'd me in the past also!

But as already mentioned, a 2-rail sweep will get you what you originally expected.

I didn't know about the micro bevel getting this to work as well?!

-Will

The 2 rail option seems to be the best. The micro fillet forces the sweep to turn a corner, but it's not a clean result - it goes through itself.

Also not mitered as I think that was the intended result.