Cost center behind an org. unit

Hi,

how can I get the cost center assigned to an org. unit ?? I am not talking about relationship A011; this works only if the relationship is available in the object´s master data. The problem is when the cost center is inherited from the org. unit above or from the one above this one or from .....

Another problem is when the position is vacant; I cannot read IT 0001 for the employee.

Is there any function or BAPI for that ??

Thanks a lot.