Getting data from a table into Custom tab of PO

Hi Expert,

Right now, i am doing enhancement for purchase order by using "MM06E005". in the subscreen, added field of employee from HR table:

my objective is: user select employee ID then program will select employee name, department and position from employee master data.

here is screen of PO:

user is able to select employee id but no data of employee.

Please kindly advice.

Thanks,

RTN.