I just completed a frame with the same situation. I just got some 4" angle iron in 2' lengths and predrilled (3)3/8" holes in each: 2" from each end and one in the center. I did a conventional first floor frame so I bolted through the ribbon and joist headers using large fender washers with star locking washers as well. I mounted these all around the perimeter with 2' spacing between them. I just had to remove the sheetrock where the brackets fell so they would tighten up against the foundation and sill. I could still tar the inset pressure treated 2x4 on the panel bottoms and lag up through the lip to them. It worked great and 3 years later there are no signs of any sag. Using a light weight siding material is probably a smart move. I used vinyl shakes; it looks awesome.
