Preserving picture-phone number link during phonebook sync?

How can one preserve the association between phone book entries and
picture during a V600 to V600 phone book sync?

Associating a phone number with a picture is a tedious process, some
some quick way to do it or at least preserve work done would be welcome.

MPT does not provide an apparent method (if it is possible at all).
Poking around in the file structure of the V600 using P2K does not
reveal any clues.

allez