The best way to achieve the desired functionality is to create your own custom wsp solution. In order to do this you can do the following steps.
1. Rename RadEditorMOSS.wsp to RadEditorMOSS.cap.
2. Extract the archive by using some archiving program such as winrar.
3. Modify your configuration files, which are located in the Resources folder.
4. Now here comes the tricky part. In order to rebuild the wsp solution again, you need the RadEditorMOSS.ddf file, which comes with the source code of the RadEditor for MOSS. If you have a valid license agreement you need to open an official support ticket and I will provide you with the needed files there.
I hope this helps.
the Telerik team