Could you not just use thickened epoxy and glue them on? Of course you drive screws, rivets etc whatever your going to do through the frames. This way, you don't put holes through the plank right beside the frame holes for nails ( I'll presume you're going to rivet her). You still have the connection of the thickened epoxy, which is out of the sun so less prone to fail ( according to Larry, it's the sun that causes this to happen so down there it shouldn't be an issue) If it fails, you're still riveted through the frames RIGHT NEXT to the floors and you don't pierce the floor's endgrain possibly promoting rot. I think this is an area where even a traditionalist (you and I both) can agree that it would be acceptable to use the googe.
Caveat, I'm not an expert and have yet to build so take my advice with a grain of salt and wait until the big guns chime in.