where are customizing data changes stored

Hi all,

I need to get the details of the data in the transaction FTXP(Maintain Tax Code) before and after changes.

Normally all master data changes are recorded in tables CDHDR and CDPOS and could be retrieved using function module "CHANGEDOCUMENT_READ_WITHOUT_ED". But FTXP being a customizing transaction, is not reflected these tables.

Can you tell me the table where I can see all customizing changes and any function module which can help retrieve them.

Thanks in advance

CMV