Create a session extension. Add a table selection for tccom110, select field cbtp and code the where-clause: tccom110.ofbp = tccom100.bpid. Note that this only will work if all your business partners have the sold-to role, otherwise the business partner overview will not show the business partners without sold-to role. If not all business partners have the sold-to role, create instead of the table selection a calculated field of type 'nested select' and code
select tccom110.cbtp from tccom110 where tccom110.ofbp = tccom100.bpid
See the Extensions Development Guide for more information.
There is no need to copy the session to your own VRC and to change the form definition. The field will be automatically added to the overview. With form personalization you can put the field in the desired location.