Outlook does not support importing to a custom form, nor importing custom fields. You would need to write your own import code or use a third-party tool. See
http://www.outlookcode.com/article.aspx?id=23
"Ken W" <Ken W@discussions.microsoft.com> wrote in message news:9EACA862-7242-4547-BC0D-F969613E781D@microsoft.com...
>I created a new contact form called XX and managed to change the message
> class using the Omsgclas.doc utility. I was even able to change existing
> contacts to the new XX form. When i add a new contact manually the new XX
> form is used.
>
> However when i import contacts, the old default contact form is used. How do
> i change the default to import contacts into the new XX form?