but I'm stopped in the last part of this, exactly in 5.a and 5.b my
Did you performed steps 5.*? What was the result?
BTW, GMF is not generating providers for ProjectExplorer in RCP mode, so
I suggest you to generate diagram in non-RCP mode (you'll have org.eclipse.core.resources
plugins in your platform) and use this code in an "RCP+resources" platform
you are actually going to work on.