Microsoft Word and Mathtype - an impossible marriage?

I tried to made portable (ThinApp 4.7) the following two apps, on a WinXP environment:

MS Word 2003 +  Mathtype 6.8 (latest version).

Mathtype is the Pro version of the (pre-Office 2007 exclusive) MS integrated Equation editor. It is necessary for MS Word files that are passed to publishing houses.

In my attempt, I found the following strange pattern:

1. If I virtualize just MS Word 2003 with its own equation editor, the equations are made and open correctly. This was not true, as far as I remember, when I used ThinApp early versions (4.0 for instance).
   
2. Yet if I virtualize also Mathtype with Word, I had the followign result: The equations are created OK, but they cannot be reopen with the following warning: "The object was created in Equation. This equation is not available....etc". This occures also when Mathtype is already open as a server (a feature that leaves the application in the taskbar).
   

Is there someone that can help in understanding if the marriage is possible or not? I know that the issue is that of Ole/com objects also used by Mathtype. But it seems strange that scenario 1 works, and scenario 2 it does not.

Thanks for any feedback.
Anthony