I wrote a CDO 1.21 Contacts interface about 2 yrs ago.  At the time,
CDO contacts were not fully documented/supported by MSFT.

I had problems getting a new contact's Email address to register in
the user's personal address book.  The only way to get the new
contact's address into the address book was to open and save the
contact from within Outlook after CDO had created it.  This was
attributed to undocumented properties that only Outlook could create.

One suggestion we got, from usenet, was to create a blank contact
"template" in Outlook.  Creating it in Outlook implied that the
"magic" properties would be set on the item.  Then, rather than
creating the contact from scratch, our process actually used CDO to
copy the template into the contact folder and update the fields with
the values of the contact that was being "created."

Contacts created like this work correctly with the address book when
you send them messages from the Inbox.  However, when you select "new
message to contact" by right-clicking in the Contacts folder, the mail
would be sent to the original "template" address.

We have to do a little more work with this application, and I'm hoping
to fix this behavior.  A couple years ago, the address book problem
(regarding the magic "Outlook" properties) was pretty well known in
these newsgroups, as was the solution of using a template.  However,
we didn't expect the problem associated with sending mail from the
Contacts folder.

I've been led to believe that MSFT (or MSDN) has since published more
info about creating contacts, but I don't know if this addresses any
of the address book quirks.

Can anyone comment on the relationship between Contacts and the
personal address book, and the state of the art with regard to getting
new contacts fullly recognized by the address book?