Systematic reuse of software artifacts has been an elusive goal for several years. Service-Oriented Architecture (SOA) has been touted in recent years due its promise of fostering reuse. Even so, reuse with SOA continues to be limited due to the lack of formal techniques for extracting domain knowledge from existing reusable software assets. In this paper,we present an approach that extracts the domain knowledge and service abstractions from design diagrams of existing software solutions and represents it in a form that can be reused in new projects. We have implemented our approach and preliminary results indicate that both domain knowledge and service abstraction thus extracted can promote reuse of software assets to a large extent.