normally I use SVG
in the Project you can see an example with an SVG mask. The apple logo 
svg_mask_apple_logo.hype.zip (126.9 KB)
You have to create a file in Adobe Illustrator PC-Mac / CorelDraw PC (or other similar app).
Copy the code of the svg file in a text field (inner HTML).
Use the same background color for filling.
hope this helps
Michelangelo