Custom engineered products require an engineer-to-order approach in development, quotation preparation and order processing. This work reports the result of a three-and-a-half-year project were the objective was to develop means for implementation and management of computer support for engineering design and production engineering of customized products. Efficient re-use is essential for success and decision is identified as the core concept to trace tasks executed, knowledge used, design rationale and artefacts developed throughout the product realization process.