Found this at World Market:
Tried it without filling the holes in the "soap holder", but all the lather went out the holes into the mug, no good. So I decided to plug the holes with a hot glue gun, after which it works great! The "soap holder" is a little small, but a little trimming and tamping solves that issue.
Here is the process and result. I don't know how long the hot glue will hold up, but if it doesn't, I will remove the hot glue and replace it with epoxy.
(and I had a couple of more pics, but didn't know there was a limit of 5 pics per post)