I was not able to use external classes at version 4.
Maby with later releases the binding becomes clear.
For version 4 i was simply adding sourcecode directories :)
for the classes:
neuroph...
gwt-text
gwtwidgets
....
ufff
....
gwt 2.6
google appengine 1.8.9
neuroph 2.7 ! (( 2.8 is comming ))
gwtext 2.0.6
gwtwidgets 0.0.4
......
!!!
In all bibliothecs above, the .gwt.xml files added manual.
Verry much work, but it is easy after understanding, what and how it is working.
Also eclipse is showing verry nice all classes which need .gwt.xml files.
With the com.jar in version 4 I copied simply the whole stuff.
In com.external.jar is the external sourcecode!
Please let me know if there are questions andyhubers@aol.com
Have fun :)