A detailed description how to create .dsnd files using Addictive Drums can be found in AddictiveToDSND.pdf. This description has been written by digitalDrummer and put on this site with his kind permission.
The midi file referred to in the description can be created with DSoundTool as described here.
Note: digitalDrummer is world-famous in the world of electronic drumming because he is the one behind the free online magazine digital Drummer. If you have the slightest interest in electronic drums you should really check this out! Often there is information that is of direct relevance to 2box owners.