The product line for software systems (PL) approach has been touted recently as one of the most promising development approach for gains in product quality, time to market and cost reduction. The approach is complex and must be tailorable to situations in which its characteristics may be of interest for adoption within a development environment. We first present in this short position paper a succinct overview of the main entry points (context) for PL adoption experienced so far within our technology transfer context. We then put a particular emphasis on the reengineering entry point in which we describe what we think are the main possible adoption scenarios. Throughout the paper we emphasize the contribution of (reference) software architectures so as to highlight the key enabling role it plays for the PL approach.