The relationship of the multivalue field should go through S_PARTY_PER table. Do not confuse this with the positions that can see the Employee or Contact record; that relationship goes through the S_POSTN_CON table.
This user property is ignored when the business component is used within the EAI or Siebel Adapter context.
You can inactivate and modify the values for this user property. You can also create new instances of this user property as needed.