I want to add a custom field for a phone and I want it to be displayed in
the contact form on the phone drop down list.

Is it possible? How?

In more details:
I want to add a field for "Business 3". I know how to add this custom field,
but I don't know how to tell outlook to add this item to the phone selector
enumerator.
In other words - When the user open the contact form and click on one of the
drop down phone button, I want this "Business 3" field to be shown in the
list.