Typically when working with /Outlook/ contacts it is more reliable and more
flexible to initiate the merge from Outlook - i.e. go into Outlook, select
some contacts, then open Outlook Tools|Mail merge..., study the options, and
go for it.

Unfortunately, as far as I can tell, if you try to start from the contacts
lists in Business Contact Manager Contacts, there is no similar facility,
and as far as I can tell, it is not possible to add one.

If you prefer to do it the other way,
a. be aware that the field names of Outlook contact fields differ depending
on how you get the contacts,
b. someone recently posted the following suggestion which seems to me to be
a good thing to try first: