thierry st malo, let me respond based on my understanding of your question. Basically, you're asking whether it's possible to use DarkBASIC Professional plugins with applications that were developed with DarkGDK.NET. The answer to this question, is no.
Not directly anyway. DarkGDK.NET uses a common class object called CDarkGDK which exposes all of the various modules of the toolkit, i.e. IdgdkBasic2D, IdgdkBasic3D etc etc. DBP plugins have no concept of these interfaces, and therefore cannot be used directly.
The author of each plugin needs to reimplement the plugin using the DGDKPlugins.dll managed DLL file that accompany's DarkGDK.NET, so that the plugin code inherits from the CDGDKPlugin class. The DarkGDK.NET provides both a C# and VB.NET sample that inherits from CDGDKPlugin to show authors how to create, or convert their respective plugins to work with DarkGDK.NET.
Both the ODE Physics plugin and CSM Cartography Shop map importer have been converted. I've also been working on the Nuclear Glory Physics conversion although work committments have slowed me up on this.
As for other plugin developers, if they need assistance, I'll try my best to help.
Paul.