This is odd, it SAYS invite only, and I never got it, but I registered no problem (which I couldn't on the 75% one). This could easily be explained by a wrongly deleted email, or something that never got to me or whatever. BUT, after registering successfully it still says "Please note that some promotions are offered by invitation, so bonus miles for those promotions will be credited only if you have been invited to participate and have fully qualified for the offer."

This leads me to believe that even though I registered, because it was never sent to me I won't get it, just based off the wording. Worth a shot though.