Can anyone tell me exactly what type of soil I need for a juniper bonsai?

Keefer wrote: Can anyone tell me exactly what type of soil I need for a juniper bonsai?

Yep. It's under the Species guidelines, top of the page. You'll need to read the How To / Repotting chapter first, including the link on that page to soil mixes.

I would use a very free draining soil mixture since junipers don't like being on the wet side.