- Browse the external systems in your BDC service application.
- Click through to the settings of the external system that corresponds to your BDC model.
- Select an appropriate Authentication Mode for your Secure Store Target Application (Impersonate Windows Identity or Impersonate Custom Identity).
- Provide the target application ID for your secure store target application.
What you actually need to type in this Secure Store Implementation field is the fully-qualified type name for the secure store provider. Unless you've built your own secure store provider (in which case you're the ultimate SharePoint guru), this value will always be the same:
Microsoft.Office.SecureStoreService.Server.SecureStoreProvider, Microsoft.Office.SecureStoreService, Version=22.214.171.124, Culture=neutral, PublicKeyToken=71e9bce111e9429c
Copy that typename into the Secure Store Implementation field and you should be good to go. I've had to hunt this value down on several occasions, so hopefully having it here for easy copy-and-paste will come in useful.