Developing Ambient Intelligence applications is a very complex task since it implies dealing with low-level software and hardware resources. The use of a middleware platform may alleviate this task by providing a set of high-level and platform-independent services to these kinds of applications. Nevertheless, the tendency is that the middleware deployed in each device has a flat and homogeneous architecture, although these devices and the requirements of intelligence environments are heterogeneous. This implies the middleware software deployed in each device normally contains more functionality than strictly required, leading to waste resources so scarce in lightweight devices. But the configuration and deployment of a minimal middleware customized to a target platform is a complex task, due to the diversity of hardware and software present in devices and the variable requirements of ambient intelligence applications. In order to solve these shortcomings, we propose to customize the piece of software related to the middleware platform by using a Software Product Line engineering approach. This paper presents an innovative configuration process for a software product line for ambient intelligence middleware where a minimal set of high-level parameters needs to be specified. So, the software engineers for this kind of systems can automatically obtain customized middleware by simply specifying this high-level information.