Networked devices, such as consumer electronics, digital media appliances and mobile devices are rapidly filling our everyday environments and changing them into ubiquitous spaces. Composing an application from resources and services available in these environments is a complex task which requires solving a number of equally important engineering challenges as well as issues related to user behaviour and acceptance. In this chapter we introduce CADEAU, a prototype that addresses these challenges through a unique combination of autonomic mechanisms for application composition and methods for user interaction. These methods differ from each other in the degree to which the user is involved in the control of the prototype. They are offered so that users can choose the appropriate method according to their needs, the application and other context information. These methods use the mobile device as an interaction tool that connects users and resources in the ubiquitous space. We present the architecture, the interaction design and the implementation of CADEAU and give the results of a user study that involved 30 participants from various backgrounds. This study explores the balance between user control and system autonomy depending on different contexts, the user's needs and expertise. In particular, the study analyses the circumstances under which users prefer to rely on certain interaction methods for application composition. We argue that this study is a key step towards better user acceptance of future systems for the composition of ubiquitous applications.