Hi,
Check the PAM at http://service.sap.com/pam. SAP ERP EhP 4 (SAP Basis 7.01) is not supported on Sybase. Hence you do not see the option to export the system to Sybase in the report smigr_create_ddl.
You would need to upgrade the system first to EhP6 and then export the same. Check similar thread at: Is it posible to migrate SAP ECC 6.0 EHP4 oracle database to Sybase database
Regards,
Srikishan