Wireless sensor networks can monitor different types of physical phenomena and are able to provide a diverse set of context data to interested clients. Allowing mobile pervasive computing devices to access such data requires solutions for routing messages between mobile devices and the static sensor network. This paper presents a novel approach that addresses this problem with the help of symbolic coordinates. It requires only a small amount of topology information distributed in the network and allows mobile devices to send messages to arbitrary areas. The routing task is split among the client nodes, which specify a symbolic source route, and the sensor nodes that handle node-to-node routing. The paper describes the algorithm, specific challenges associated with its design and gives an extensive evaluation of the approach and its properties, showing that the use of symbolic coordinates in these environments is a viable alternative to more traditional types of routing.