HOW TO ADD A MANGONEL IN THE VANILLA MOD?

[Ishan]

OK Guys i need help big time I'm working on a mod and i want to add a new unit i.e a mangonel.
i know it can be added in the retrofit mod but how to add it in the vanilla mod. would somebody just plz help on this one.
I have already added Greek fire throwers in the vanilla mod.

Once again my question is "HOW TO ADD A MANGONEL IN THE VANILLA MOD?" WHAT ALL FILES ARE REQUIRED TO MAKE IT POSSIBLE.
PLZ PLZ HELP

[=NF= Vasileios_the2nd]

Well, shouldnt this be the same as with the Greek fire throwers?