It's a misconception that Ground = discharge. The third prong on the EP34 supplies voltage. Electrons flow from negative to positive. What we think of as ground is actually the bike's system to provide voltage. It's the reason why people always tell you to disconnect the negative cable from the battery before the positive.
I've been reading your posts and I would suggest using SPDT relays.
http://www.bugmanweb.com/gsxr/turnsignal.html scroll down to half the page and check out the "Madness" method. It's what you want to do.