Hi William,
The mixed resin is going to stick to the ceramic/clay surface. Even if a mold release was applied to keep the resin from sticking, I doubt you will be able to get the resin out since the clay isn’t flexible like a plastic mold. You need to be able to pull or twist the mold to get it to separate from the resin in order to demold it.
My best suggestion is to get a brush on silicone molding material (we don’t sell anything like that) and brush that over the surface of your ceramic template. You can then use that as the mold (with the proper supports) for your resin.