After having done, step by step + verifications, an installation similar to the one described here, i had several problems: impossible to import classes from the main package into the main class, problems with importing the mx library (eclipse found problems in the Macromedia classes!!!!), and several other funny things. But eventually i managed to make everything run.
Here is the result (eclipse project, zipped with standard mac stuff added automatically) -> download
Proposal: 1 project including all the files (libraries+projects) in the "src" folder. For each project, just declare a specific sub-folder in src and configure another .flashout ... a bit dirty, but working. All this because 1 thing: for the compilation to run, all classes except the main one have to be in one folder. This src folder is used as "Directory for MM's core classes". See Eclipse -> Preferences -> Flashout.
That's the best solution at 04:05. If somebody has a better solution -> contact