Kuryakyn sells some offsets that you can put on top the guards, using your current Hwy pegs.
Called
right angle cruise mounts (offsets). #4507
I think you will need one inch clamps up top.
You need the offsets and one inch clamps, and reuse your pegs. Obviously, you can slide the clamps as far inboard to the guard mounts as they will allow. Dually pegs might interfere with the guard if directly over the guard bar, unless you flatten them out, angle-wise.
http://www.amazon.com/Kuryakyn-4507-Right-Angle-Mount/dp/B0050DCHTEIt's not clear if these on Amazon come with the small iso pegs in the picture or not. You could use your duallys, or small isos, but don't get large iso pegs (they are huge and intended for control foot pegs).

I have 4050s with duallys and a set like you have on the guards with small isos (on two bikes), and I like to lay my boots over top of them from time to time to stretch out. I find it much more comfortable on my Achilles tendons laying them over the fatter duallys than across the small iso pegs.