Siren breeding attempts

Hi! So I have been fascinated with the idea of breeding my greater sirens for some time now. I know captive attempts haven't been successful from what I can tell but I know people have intentionally bred dwarves and at least accidentally have bred lessers. The only info I can find about nesting is that they've found eggs in clumps of peat caught in water hyacinth roots. Right now they are in a 250 gallon outdoor glass aquarium with lots of vals planted across the ground, large wood and rock hides, water lilies and a thick layer of a mixture of lily pads, water lettuce and water hyacinth across the entire surface of the tank. Does anyone have experience with lesser or dwarf breeding? I figure the outdoor tank will potentially help with noticable seasonal changes but I know very little else about what people have noticed when eggs are laid. Right now my babies are 28 and 26 inches long, and I'm 90% sure I've got a male and female.

There was a study done on lesser sirens breeding. The breeding was successful, but if I remember right the eggs didn't survive. I read it a couple years ago. I found the name and authors. The only place I've been able to find the article online makes you pay for it. Maybe you can find it in a library or somewhere.

Biting in the Salamander Siren intermedia intermedia: Courtship Component or Agonistic Behavior?
John E. Fauth and William J. Resetarits, Jr.
Journal of Herpetology
Journal of Herpetology
Vol. 33, No. 3 (Sep., 1999), pp. 493-496 (4 pages)
Published by: Society for the Study of Amphibians and Reptiles