Adaptive hypermedia is a relatively new direction of research on the crossroads of hypermedia and user modeling. Until very recently, little attention has been given to the complex task of authoring materials for Adaptive Educational Hypermedia (AEH). An author faces a multitude of problems when creating a personalized, rich learning experience for each user. In this paper, we present an authoring tool that allows to the authoring of adaptive educational hypermedia. Based on a client/server architecture, the system allows several authors geographically dispersed to collaborate to produce such AEH together. We consider, within this framework, the creation of a shared workspace gathering all tools necessary to the cooperative development task. The architecture of the authoring tool is outlined.