The first attempt was to import the eclipse project into netbeans. But this was not successfull.
The eclipse project has one master project which encapsulates the others and there was
a hint about "The Eclipse project ... has a source root ( .... )".
So I used the free-form project with the existing ant file.
The problem were subprojects.
In the Master-project I referenced all including projects by name in
the original has an entry like
If you have everything inserted, the subprojects are opened and you can change to the
source with "Go To Type".
ATTENTION: When you change some project settings, the subprojects are lost!!!
I used NetBeans 6.7.1