Hi Luke,
If you have used the automatic extension onaboarding feature in the SuccessFactors Provisioning it means you have not assigned your company administrator users to the Extensions Administrators RBP Group.
Please follow the "2.1 Defining the People Pool for Managing Extensions" section from the SAP HANA Cloud Platform, Extension Package for SuccessFactors implementation guide (http://service.sap.com/~sapidb/012002523100013621492014E).
Regards,
Stanimir