I don't know what various methods the guys who build ICF full time use, but that is exactly one of the reasons I will be using a 2 x 12 sill plate on the top of the gable walls of my house!! On the other walls, perpendicular to trusses, I'll be using 2 x 10, flush to the inside for sheetrock nailing. At a buck a foot for 2 x 12s well worth the investment.

I found a solution and thought I would post it in case anyone runs across this problem.

You could use a taper top form or use a saws-all to make your own taper. This way you can still use the embedded hangers. this is what I did on each end of my house to support the end truss that would have been sitting on foam. The embedded hangers seem to me to be the only way to go structurally. I used one called a HETA. I think it's made by Simpson. They also make a metal plate for the truss to sit on so you don't have wood to concrete.

Greg

Looks to me like more work than a sill plate, but maybe not. But, I see you spec out 2 x 6 PT. My lumber quotes show 2 x 12 Doug Fir a few pennies less per foot than 2 x 6 PT. Better wood too, plus gives me the nailing edge for sheetrock.

Thanks for the replies.  We considered using a sill plate but we have been told that the embedded anchors are favored by the inspectors (ie the county) and the new code that Florida enacted in October.  I could use non pt lumber and install 6 mil vapor barrier and save a bit, but I will probably stick to the pt.   There are only four trusses that we will have to install with the 2 x 6 pt.  It would probably be easier when setting trusses to install a sill plate so that we wouldn't have to be precise with the layout, but I think the benefits will out weight the time. 

If you have any concerns about using pressure treated wood inside your home, then you might want to look at this site: LINK