Section 2 introduces the concept of protocol object as defined in BAST, and how it helps to structure distributed systems and to deal with failures. Section 3 discusses why inheritance alone is limited in supporting flexible protocol composition and presents how we applied the Strategy pattern to break these limitations. We also show how the Strategy pattern is transparently used in a recursive manner, and we present what steps have to be performed in order to extend BAST through protocol composition. Section 4 discusses various design alternatives, and compares our approach with other research works described in the literature. Finally, Section 5 summarizes the contribution of this paper, as well as some future developments in the BAST framework.