How may I set a Partition Range in erwin for Teradata?

How do I add a Partitioning Expression for a Teradata Partitioned Primary Index DDL regarding 'RANGE_N' as below in order for Teradata to accept the Partitioning Expression?

PARTITION BY RANGE_N(PROD_DT BETWEEN DATE '1985-01-01' AND DATE '2015-12-31'
EACH INTERVAL '1' MONTH , NO RANGE)

Solution:
Follow these steps to add an Expression in the Partition Expression Field:
Right click the table and go to Index Properties

Select the Options TAB.
Check the box of Primary Index for the column.
Add an expression in the Partition Expression Field.  For example, 

RANGE_N(PROD_DT1 BETWEEN DATE '1985-01-01' AND DATE '2015-12-31' EACH INTERVAL '1' MONTH , NO RANGE)) ;