This paper introduces a novel architecture for implementing content-based pub/sub communications on top of structured overlay networks. This architecture overcomes some well-known limitations of existing infrastructures, i.e. lack of self-configuration and of adaptiveness to dynamic changes. This is achieved by devising a mediator stratum between the rich event subscription semantics of content-based pub/sub systems and the standard logical addressing scheme of overlays. The paper describes details of the design and provides considerations in selecting the subscription-to-node and event-to-node mappings suitable for the solution. We identify the lack of native support for one-to-many communication by overlay networks as the main impediment for efficient system operation. The paper introduces a novel primitive for one-to-many message delivery, showing through simulation how this can improve performance of the architecture. The simulation study also shows performance comparison between the different mappings proposed as well as evaluation of other optimizations discussed in the paper.