But, according to gateway terms, isn't "around the corner" equivalent to a months worth of time?
They have pretty good PR. They word it like this to make sure they can't be held accountable for missed release dates.
I don't know if you have any experience with reverse engineering, but this is the right way to go. It's hard to make a prediction because you may or may not run into roadblocks along the way.
Things can go butter smooth and give you very little trouble, or things go so bad it will take a much longer time to complete. Kinda like when we found out there was no info on enemy AI for a game server my team has been working on. Result was we have to do all enemy AI from scratch. It was something that wasn't accounted for, and we'd have people with pitchforks if we had a set release date.