How do you get a hero chaos chao to breed a dark chaos chao

Chaos chao dont breed at all!

lol-
when it's 'mating season' in one of the gardens, a chao will get flowers around it... then, either the nxt chao that walks by OR a chao you put nxt to it will like get married to it then they hop away and leave an egg. sometimes they are incapable of marring like a jewel chao and a normal chao... BABIES CANNOT EITHER. try it with a chaos choa and i guess u'll see.. no special tricks