There was a solution using either the enhancement SMOD ACBAPI01 (for oldest BAPI) or BTE RWBAPI01 or BAdI AC_DOCUMENT (for more recent like BAPI_ACC_DOCUMENT_POST) 
the status of the document to "parked" (the field T_ACCHD-STATUS_NEW is changed to 2 or 3) using an implementation of the Business Transaction Event (BTE) RWBAPI01 or of the BAdI AC_DOCUMENT
But since SAP has published 1951302 - Document parking through BAPI_ACC_DOCUMENT_POST, so only official solution is batch input 
Regards,
Raymond