Converting an Outhouse to a Composting Toilet

Looking at the building, I wondered what to do with it: toolshed? chicken coop? solar shower? And then it hit me: I want a composting toilet. This will be great to use when we're outdoors, working in the garden and orchard. Plus, it won't use up precious water (which is a limited resource here in Bulgaria) and it will give me compost (we always need more compost). :-)

I'm hoping to find a volunteer helper with handyman skills who can construct a functioning composting toilet in this building. I've purchased the crucial part - the urine separator - and I have bits of reclaimed wood and other materials which can be used.