Mike just split the process.
Each chemical is there for a reason. You main reason for usuing this product is for preserving the dead wood. The sulphur in the process does nothing in that process in the preserving of the wood. The sulphur is there to aid as a fungicide and pest control.
So just mix calcium hydroxide, (get the food grade for canning its finer ground and mixes more easily with water) and mix to sloution. Use a surfactant like dish soap to aid in whetting. It is in commercial lime sulphur too, that is why it foams when you put it on. Your tree will white up and the calcium will integrate with the pores in the wood hardening them just like the lime sulphur did.
Use a good fungicide before application of the calcium and you will be covered just like before.
You can make your own though dangerous. Just boil the calcium hydroxide solution with the addition of sulphur powder and surfactant.
Both chemicals are not banned, just together. This process is not chelated so the calcium will fall out of solution and harden in the bottom of the bottle you keep it in. Make enough for your yearly use( a cup or two?) and make it fresh each year. This is not the end of the world, we just have to be more resourcefull now.
al