Luar -
Unfortunately, the Windchill WGM doesn't support the applications you listed - Intergraph, Staroffice, ZWCAD.
Secondly, I'd like to clarify that the WWGM Toolkit cannot be used to build an integration to the tools that are not supported. The WWGM Toolkit provides some interfaces to automate some processes - e.g. programmatically import CAD files to the workspace, programmatically add models to the workspace from Windchill based on some trigger, etc.
If you just looking to vault the CAD files/documents from these tools without exposing the relationships, attributes into Windchill, you might consider zipping up the files and managing them as Documents. You can soft type the Document object to differentiate them from other regular document files (MS Word, etc.).
You should be able to use the Document approach mentioned above even with PDM Essentials (PDME).
Thanks,
Mark