I had a look at the SCoopME sources, but without diving into it: it looks like a cleaned up version of SCoop, better written and probably smaller. I suggest you use that instead of SCoop, at least until fabriceo comes up and explains what are the differences.
In fact, I had tried SCoop and then witched to SchedulerARMAVR, which is much simpler, and which I am using right now, because I do not need all the goodies provided by SCoop, it is much smaller and has the same interface as the standard Arduino Scheduler library. The only thing is that I needed to measure the stack occupancy of tasks and I had to write those functions by myself (I posted them above).