Hello Matthias,
I am currently working on improving the XML export for MS Word bilbliographies, as there are some things not getting exported correctly. I could confirm your export of the patent.
I am not sure if is possible to include the original type. Normally the type of the bibtex entry gets mapped to the type of the corresponding Word reference entry type. I will take a look at this.
If you find more errors regarding not exported fields, please add them in this issue, so that I can have a better overview
https://github.com/JabRef/jabref/issues/1750
Regards
Christoph