I have a parent table which has two composite keys: ID and NetworkCD

I need to created an many to one relationship in the parent to the child table. However the child table has an Sequence Number and also ID and Network Code are foreign keys my two question are?

1. What is the best way to create the relationship to the child in the parent mapping file.

2. In the child mapping how do you recognize and sequence number and foreign keys in the mapping file?

Currently I recieve an error saying...
Foreign key in "child table" must have same number of columns as referenced primary key in "parent table".

Im assuming this is happening because I have not identified the ID and Network Code in the child table as primary keys, however this child table has an sequence number as well.

Please advise.