SAP authentication plug-in needs to have been selected during the installation

Can anyone help me with an issue I have with the SAP authentication setup please. Unfortunately our BI 4.0 SP4 installation was installed without the SAP authentication being selected. On the setup document I have it says that the SAP authentication plug-in needs to have been selected during the installation. Does anyone know if it is possible to set this up retrospectively?

The document can be found on the following link. Setting up the SAP plug-in - Business Intelligence (BusinessObjects) - SCN Wiki

Thanks

Simon