[news.eclipse.tools.pdt] Can't reach platform-plugins from workspace

[Mirko Richter <mirko.richter@xxxxxx>]

Hi,

i wrote a plugin that uses emf, gef, gmf and oaw. I configured my 
Eclipse 3.4 in a way that it starts without any error-message and all 
plugins are installed as expected. I checked that via "Help/About 
Eclipse SDK" and "Help/Software Updates..." . In addition i opened the 
view "Plug-in Registry" and all plugins could be found there.

Anyway, if i put my plugin into that workspace it says that i can't 
resolve dependencies to plugins that are definitely available in the 
platform (as explained above).

Is there any flag to be turned on? Can plugins be configured hidden in 
any way to custom plugins in the workspace?

I also restartet Eclipse several times and "clean" for sure.

I actually made most of my experiences with Eclipse 3.3. Can anyone help?

Thanks in advance,
Mirko