Business-to-Business integration (B2Bi) is considered to be not merely an IT-issue, but also a business problem. This paper draws attention to the challenges companies within an Extended Enterprise are confronted with when integrating their systems. We primarily pay attention to coordination problems that may arise. To overcome these problems we propose the use of Enterprise Architecture descriptions. We discuss the powers of using Enterprise Architecture descriptions in integration exercises. It will become clear that doing Enterprise Architecture is no longer an option; it is mandatory. Furthermore, we present the FADEE, the Framework for the Architectural Description of the Extended Enterprise. This framework gives an overview of how companies can apply the Zachman framework to do Enterprise Architecture in the realm of the Extended Enterprise.