Large scale applications demands for more and more support of loosely coupled??distributed interactions. The publish/subscribe interactions well adapt to these??needs and because of that is gaining momentum in the Web Services community (e.g.,??WS-Events, WS-Notification). The main goal of such mechanism is decoupling??in time, space and synchronization publishers and subscribers. One current??limitation of existing standards and middlewares supporting the related??implementations is the need for the subscriber to know the topic offered by the publisher and to be able to process natively the published messages. In this paper we propose an extension of WSMX to support Publish/Subcribe interactions; the extension is adopted to support an innovative scenario??(that we call User Driven Services paradigm), where user searching for services??notifies providers through the middleware of their needs and get notified by the middleware when a provider register a service fulfilling their needs.