The only reports I am aware of came out of the Cincinnati Zoo, and were mentioned in Captive Management Conservation of Amphibians and Reptiles in the chapter by Maruska. Unfortunatley any details other than it occured are lacking (reading what was published makes it sound like they were bred over a number of years in a shoebox with paper towels.
In a slow moving stream setup, I did get the males to combat for territory after I took them down to about 4 C and some courtship behavior was observed. The females will develop eggs at a warmer temperature and the eggs can be seen through the abdomen.
Ed