Patching and Plastering - Hole in bathroom wall

Background:
I have a 4"x6" hole in my bathroom wall after taking out an inbuilt (ceramic?porcelein?) soap dish. When the soap dish came out a lot of soil came with along with whatever (concrete?) was holding it in place. This is an exterior brick wall (I can the back side of the bricks now).
Ideally, I would like to replace it with a similar fixture (if I can find it!!) or failing that , use tile to make my own soap dish (of sorts).
My question:
How should I prepare the hole for this purpose? What's the technical name for the type of wall I'm dealing with here (mudwall?)?

Thanks,
sami

Good news! I found replacements for the fixtures. I was told by the helpful gentleman who sold it to me that I should stuff newspaper into the opening and then use plaster of paris to attach the new fixtures into place. Any agreement/disagreement? Any additional advice or tips on doing this correctly will be appreciated.

Thank you,
sami