Unfired items can't be fired in a regular furnace, or anything that uses furnace recipes.

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Can you please explain further. I don't understand exactly what you mean.

What happens?
What do you expect to happen?

I think I understand now.

Am I correct that you'd like to see vanilla furnace recipes for the unfired clay bucket?

Ah, yes. Sorry for not providing more info, I was busy and just wanted to post it. However, it is not just unfired clay bucket that I'd like to see, but all the unfired items, though personally, I find the bricks to be the most important of them all.

In the latest version (1.2.1) it shows the recipes in JEI but they don't work (in the furnace), is it already being added to 1.3.0, or is this a bug?

It's an issue. Check out #97 for more info.