Ubiquitous networking empowered by Beyond 3G networking makes it possible for mobile users to access networked software services across heterogeneous infrastructures by resource-constrained devices. Heterogeneity and device limitedness creates serious problems for the development and deployment of mobile services that are able to run properly on the execution context and are able to ensures that users experience the "best" Quality of Service possible according to their needs and specific contexts of use. To face these problems the concept of adaptable service is increasingly emerging in the software community. In this paper we describe how CHAMELEON, a declarative framework for tailoring adaptable services, is used within the IST PLASTIC project whose goal is the rapid and easy development/deployment of self-adapting services for B3G networks.