How to add children and birthdays to contact

I am trying to customize the new contact form to include spouse, children
and birthdays for all. Basically would like them to work the same as the
details page birthday field, ie sets a recurring item in the calendar with a
reminder.

How does one go about this. I can edit the form to look like it should
work, in other words the fields are there, but can't get the item to come up
in the calendar. Also, is it possible to edit any other page other than the
general page? If so, how.

I realize that this is quite a bit to ask, but it sure would be helpful if I
could get it working

Thanks,

Jim