it aint actually that complicated. Its simple. You can retract the flaps once the speed is correct.
If you need a level segment to achieve that speed the most common one to use is 1500 feet but you can use anything between 400 feet and the end of your single engine max thrust limit.
When you are all engines operating you can take the flaps up before 400 feet if you want because you don't need a level segment.
Mr Greendeck, thanks for that bit of legislation. I think I need to hunt around a bit more and find that written down in the northern hemisphere now! I've sent a written request to Bombardier and I'm probably going to send it to Cessna tomorrow to see if I can get some manufacturer responses. I won't bother with Hawker, they're all a bit busy..