You can specify the driver by doing the following:
On Windows, the start file is:
%ProductDir%\connectors\OracleApps\start_OracleApps.bat
On OS/400, the start file is:
/QIBM/UserData/WBIServer43/QWBIDFT/connectors/OracleApps/start_OracleApps.sh
On Linux, the start file is:
%ProductDir%/connectors/OracleApps/start_OracleApps.sh