That is a problem, one would assume that in animals as closely related as Burms and balls seemingly are the chromosomal arrangement would be highly conserved. I'm not aware of any organisms where this isn't true however I'd imagine it isn't impossible. What I am curious about is whether two related organisms that have different patterns of sex chromosomes would even be able to produce viable offspring. I'd really like to see what sexes a male burm female ball breeding would produce because that would answer the question.
I apologize if that has already happened and I'm just not aware. Please let me know if it has.