Deriving a product from a product line means selecting and configuring existing reusable assets to meet a particular customer?s needs. The blue-sky scenario in product derivation is that all customer requirements can be satisfied by exploiting existing assets and their variability. The more realistic scenario, however, is that the customers will have additional wishes and requirements that are not covered by the product line. We therefore need integrated support for both product configuration and requirements engineering tasks. New requirements captured during the sales process need to be related to existing assets. In this paper we present a tool-supported approach for integrated product configuration and requirements engineering. We illustrate the approach using a scenario developed in our research collaboration with a leading company in the steel plant building domain.