We propose an object oriented support system which suggests solutions in multi-domain problems. It exhibits two reuse levels: (i)during the knowledge acquisition phase, a framework is provided to the experts and allows reusing of other acquisitions, (ii) this framework is given to the end-users for their real cases representation. The system mixes an hybrid approach: object modeling and Case-Based Reasoning paradigm. All the components indexed by specific objects are stored in different libraries. We introduce the concept of version for object types and instances to increase reuse and to manage their evolution.