Up from a certain degree of impairment, motor and multiple disabled children are rarely able to use conventional environmental control and augmentative communication systems. To attain this ability, in many cases customer-tailored user interfaces plus a long training process is necessary. Even learning the relation between reason and effect and experiencing self effectiveness (being able to make something happen in the environment) is the first big challenge and often an entire new experience. Hence, a technical system able to meet the needs of these users has to fulfill three criteria: (1) give optimal support to the training process; (2) support the facilitators with a tool to easily adapt the system to the rapidly changing user needs; (3) be able to grow from the first experience of self effectiveness up to a multi functional, multi purpose technical aid. The paper discusses an innovative technical assistance system developed at the Vienna University of Technology which is especially for multiple impairments and the training process. The authors look back on one and a half years of practical evaluation of the technical assistance system in a support center for motor and multiple impaired persons. After introducing the concept of the technical assistance system and pointing out its special features, two case studies illustrate the practical application of the system.