Is there an XML file in MDS for mapping OIM user attributes to OID attributes?

I am only interested in controlling the flow of user attribute transactions from OIM to OID, not the other way around. I am aware that Oracle is saying that any UDFs added to the OIM user attribute list must also be added to their auxiliary object class in the OID named orclIDXPerson. Is there also an XML file in the MDS that has to be modified (exported from MDS, modified, imported back into MDS) that controls the mapping of OIM user attributes (all of them, including base attributes and UDFs!!!) to OID attributes when OIM user transactions are presented to