SAP upgrade issue from sap4.6 to SAP ECC

Hi gurus,

We are upgrading from SAP46 to SAP ECC6.0 and observed that some of the VBAP fields are dropping in new version.

but we have used dropped fields in our custom programs (old version) , what are the ways to handle this situation in new SAP version?

Please let me know if any one faced this situation.

Sireesha P