Old question, but for future help...
When using Enhanced MetaFiles in PowerPoint:
- Insert -> Picture -> Select your .emf file and click ok
- Right click the image and go to Group -> Ungroup
- It will ask you if you want to convert it to a MS drawing object. Click YES.
- At this point the shape/image will have a thin outline. Right click again on the image and select again Group -> Ungroup.
- Select your elements and go to Format -> Shape Outline -> No fill
(When you ungroup your .emf images there will always be an empty/no fill element behind. Make sure to select and delete it.)