Business Delegate and Session Facade

What would the cardinality generally be between the Business Delegate objects and the Session Facade?

ONE to ONE. Often, the business delegate will have the same API as the session facade.

There is a close relationship between the BD and the SF. The client layer interacts with a BD. The BD would in turn, employ the Service Locator pattern to locate the SF. It is common to see a one-to-one mapping between the BD and the SF.