[JohnF]

I don't claim to have tried all permutation, but the one I have found to work is export EPS and then in Word, make sure you print to a Postscript printer. This could, of course, be a real printer but it could also be an imaginary one that you always do a "Save to PDF" option for. The trick is that Word behaves differently when it thinks there is a Postscript printer on the receiving end of the print job.

Printing to Acrobat Distiller also works since it presents itself as a Postscript device.

All other combinations I've tried result in a very poor quality rasterization somewhere along the line.