How to delete Document Workspace sub folders with Sharepoint web services?

Question

I'm trying to delete a sub folder in a dws.
This is the code I've got:

        SharepointDocs.DwsSoapClient dws = new SharepointDocs.DwsSoapClient();
        dws.DeleteFolderCompleted += dws_DeleteFolderCompleted;
        dws.DeleteFolderAsync(DWSname+'/'+folderName);

In the call back for completion I get no error codes only the message

"<Result/>"

On the msdn site here, it says this empty message signals a success. However, the folder is still there.
Any ideas what could be the problem?