If you click the link to the right of the image, you get some hints, although it is far from complete. This is it:http://csx.jp/~3dpuzzle/offset.html
I stared at it for about a half-hour before I figured out the non-pyraminx corners. There are two triangles on each face of the pyraminx core that have no attachments. The similar third of each of the four faces is the where the four non-pyraminx corner attachments go.
The more I look at it, the more I like it. I desperately need to find a decent plastic seller where I can buy thick sheets like they show on that site... cause I sure as heck don't want to (or can't!) mold all 14 pieces.