Ambient computing requires the integration of multiple mobile heterogeneous networks. Multi-path communication, in such scenarios, can provide reliability and privacy benefits. Even though the properties of multi-path routing have been already extensively studied and a number of algorithms have been proposed, implementation of such techniques can be tricky, particularly when resource-constrained nodes are connected to each other through hybrid networks with different characteristics. In this paper we discuss the challenges involved in implementing multi-path communication on a middleware for hybrid mobile ad hoc networks. We present the PLASTIC middleware, some compelling applications of multi-path communication and the main issues concerning their implementation as a middleware-provided communication primitive.