Not all records are updated in DSO

Dear Friends

     My Scenario is SAP - FM -> DataSource -> InfoPackage -> DTP ->Transformation - > DSO.

     I have 896 Records in my PSA , but when I run DTP to load the data in DSO only 817 records are added, rest records are not updated.  I have supplied

Purchasing organization             0PURCH_ORG

Purchasing Group                      0PUR_GROUP

Vendor                                      0VENDOR 

BW: Document Number              0DOC_NUM

BW: Document Item Number      0DOC_ITEM

Material                                    0MATERIAL

Accounting document number    0AC_DOC_NO

Item in Material Document         ZZEILE

as key fields of DSO.

can you suggest me what could be possible reason for not having all the records.

Regards

Naim