As one would expect, Ed's solution is ingenious and simple. I'm compelled to add the caveat that this may not satisfy "hold-down" requirements. A hinge flap secured to the bottom of the post might simply be secured by screws into end grain...not very yielding against pull out. However perhaps used in conjuction with a product like those offered by www.timberlinx.com (similar concept to furniture barrel nuts) and a hinge would be satisfactory... Although the hinge and bolt head maybe a problem, perhaps timberlinx would offer a tapered bolt head, and the hinge might have countersunk holes.... In this case I would weld, in the prior case welding seems comforting, but I have little faith the hinge would be taxed before the screws pull out of the end grain.