you are on which release?
You can use IT0105 or make your own iview to update these details, many do this.
00105 is standard delivered and others can be added easily from EHp5 onwards
Introduce new infotype
http://help.sap.com/erp2005_ehp_05/helpdata/en/38/fd1f7ed337404cae5c8a2341dbdca4/content.htm