FWIW...
In the past when I submitted a CYMK Tiff file to a client I've used the Xara Plugin successfully but of course the image never looked right when I viewed afterwards in my viewing software (Thumbsplus). But low and behold I accidently opened it in Windows Imagining Preview software (a Kodak program that comes with Windows) and Kodak's software corrects the view back to RGB colour - interesting...

I don't know if this little bit of trivia would be of use to anyone but I thought I would pass it along.

Merry Christmas!
Phillip