Problem in material determination

Dear SAP Expert,

We have a manual material determination procedure in sales, when we create sales order with reference to contract system show a list of materials than we choose material from the display list and save the order.

recently we created new material code which needs to be added in material determination list but i m not getting the tcode where this new material code will be added with the existing one.

can u please advise how to add new material code in existing manual material determination list so tht we can sale our new material.

warm regards

parul