How do I set the parameter precision so that it returns 2 decimal places?

This is my code:

            Decimal defaultValue = 0.00M;
            IDbDataParameter param1 = this.CreateParameter("@PolicyHeaderPK", policyHeaderFK);
            IDbDataParameter param2 = this.CreateParameter("@SuspenseAmount", defaultValue);
            param2.Direction = ParameterDirection.Output;

            // how do I do this: 
            //param2.Precision = "18,2";

            // Call the stored procedure and pass the parameter
            IDbCommand cmd;
            this.ExecSprocScalar("PoliciesGetSuspenseAmount", out cmd, param1, param2);

            // Retrieve the value from the command object
            IDbDataParameter param = (IDbDataParameter)cmd.Parameters["@SuspenseAmount"];
            Decimal suspenseAmount = (Decimal)param.Value;