I tried looking for these and Sri Lanka's a few months ago and wasn't able to find anyone in the country that had them. I also asked Mustafa over at petshrimp.com since he is where I originally got both of them from but he no longer has them either. Let me know if you find them though as I would love to have them again.
They have a larval stage but they don't need brackish water for them to breed. They are basically treated like any other dwarf shrimp. I used to have them back in 2009-10 and they didn't seem to hard to breed but I just didn't focus on them enough and when I moved I ended up losing the few I had left.