In CRM table BUT000 contains the Partner base data.
With view CRMV_BP_FRG0140 it is possible to link the BUT000 table to table CRMM_BUT_LNK0141 containing Sales Org assignments per Business Partner.
However this only works for BPs that have not been created/maintained with BP Templates. If they have been created/maintained with templates, the view returns no Sales Org data. Instead this information is implicitly defined by a default value linked to the template used. The template is to be found in table BUT0TP.
Easiest way to get the correct Sales Org from the BP ID is to use FM CRM_BUPA_GET_BPS_SALES_AREAS which will return the correct Sales Org irrespective of how it has been maintained. This FM is part of the “CRM BP Read Access” CRM_BUPA_READ Function Group.
See also the following post: http://scn.sap.com/thread/1640107