The ignition for the 1000 doesnt plug into the 600, i can tell you that much
I have a extra ignition, with key, that works... if you want to buy one cheap
But have you checked all the obvious? Have you tried to turn the handle bars from one way to another (they move a little even though its locked) if it is turned too hard to one side, the key wont turn on (or off) at all, just move the bars a little and turn it. The same thing happens if you take your key out of your car completely,and then turn the steering wheel real hard. The wheel will lock, but if you try to put your key in, you cant turn it, unless you turn the wheel a little bit first. Im not sure if this is what is going on, but i can see it happening to someone newer (relative to your post count).
If this doesnt help, i DO have an EXTRA ignition and key (meaning i have no use for it right now) that i am willing to let go of.All you gotta do is offer me enough to take it to the post office and put a couple bucks in my pocket for the drive.
Keep in mind you then have two different keys for your locks, so if you keep putting the wrong one in, over time, im sure you will end up in the same situation. I would keep the keys on two different rings or atleast mark them.