Hi Charles,
I have not but I have a suggestion for you:
1 - Get the .ascx.resx site files from the DMX folder \DesktopModules\Bring2mind\DMX\App_LocalResources - This is the folder that stores the resource files;
2 - There are not that many files so just do a simple text search by the current email message;
3 - Once you find it, replace with the message you want;
If this text is really in the resource files, then this process will work.
Cheers,
Aderson