Problems with BAPI_DOCUMENT_CHECKOUTVIEW2

We try to check out solidworks-files from the KPRO-Server to another server or to a local PC. We are using the BAPI BAPI_DOCUMENT_CHECKOUTVIEW2. Testing online in SAP the Bapi works perfectly. But when we use the java-source, it doesn't work at all. Did anybody use this BAPI with the JCO successfully?