Requirements traceability is essential for developing software systems of high quality. Whereas the traceability of the refinement, deployment, and use of a requirement is called post-traceability, the traceability of a requirement back to its origin is named pre-traceability. In this contribution we present a requirements engineering environment, called PRO-ARTProcess and RepOsitory based Approach for Requirements Traceability, which enables requirements pre-traceability. PRO-ART is based on three main contributions: a three-dimensional framework for requirements engineering which defines the kind of information to be recorded; a trace-repository for structuring the trace information and enabling selective trace retrieval; a novel tool interoperability approach which enables (almost) automated trace capture. In addition, we report on experiences made with the first prototypical implementation of PRO-ART and the resulting re-design and re-implementation, called PRO-ART 2.0, which mainly addresses scalability problems faced with in real applications.