I got an issue with a docx file where the SmartArt diagram is missing when saving to XPS. As far as I can read from this page, the feature is not supported yet but according to this blog post, you have been working on it for over a year. Can you give an update on the status of this work? I have attached the document in question, if it will help you say anything specific to this case.
Thanks for your request. Currently, SmartArt objects are preserved upon converting between formats that directly supports this feature, i.e. DOCX, DOTX, DOCM, DOTM and Word 2007 XML formats. Preserving SmartArt objects in other formats requires converting these objects to images. This feature is not yet supported. Currently, we plan to support this feature before end of September. You will be notified as soon as it is supported.