The site I pointed you to in your COM post also has "ShellExt: This is a shell context menu extension which will add a menu entry "Edit registry" to explorer's context menu if the type of the selected file is "registered", that is, an entry ".xxx" exists in the registry ("xxx"=file extension). Written in ASM, source code is included. Recompilation requires MASM32 package. " This from
http://www.japheth.de/