Create a view of the source table, so that the column names match the target. For example, notice how I changed EMPNO to EMPLOYEE_NUMBER using the view below:
CREATE OR REPLACE FORCE VIEW EMP_VIEW
( EMPLOYEE_NUMBER, EMPLOYEE_NAME, JOB,
MGR, HIREDATE, SAL,
COMM, DEPTNO)
AS SELECT EMPNO, ENAME, JOB,
MGR, HIREDATE, SAL,
COMM,DEPTNO
FROM emp;