In order to develop Document-templates that are compatible with Word, use the following steps.
The most important rule, use XML not MHT.
Prepare the template in MS-Word
Highlight the locations where CxScript needs to be inserted
Save word-document as .XML
Open file in a text editor like Notepad++
Locate and substitute the highlighted locations with CxScript
Save file and rename in to .doc
Upload it as Template