How does Metamorphosis really work?

I tried playing around with Metamorphosis, but after my hero returned to normal, it forgot all of it's abilities; All the abilities became unlearned. I don't understand why it happened. I thought it was because of the Engineering Upgrade I put on it, but it wasn't. I made sure that both unit's were exactly the same, except for their model file.

Since my tinkering around with metamorphosis didn't work, does someone mind telling me how to set it up correctly? And if possible, tell me what happened to my Metamorph?

I belive u have to include the unit it transforms into in the "Techtree - Dependancy equivalents" property.