Performing global node mobility requires to support seamless vertical and horizontal handovers between different network providers and technologies. The optimization of the handover processes requires not only continuous network services, but also continuous service performance. In this paper we present a novel design approach based on autonomic components and cross-layer monitoring and control to optimize the performance of the WiOptiMo system, which provides seamless internetwork roaming by handling mobility at the application layer. We also distinguish from past work, in that we pragmatically followed the approach to rely only on existing technologies, deployed protocols and lightweight calculations, such that our system can be straightforwardly implemented as it is on most of the currently available mobile network devices. We report results from some simple real-world experiments showing the benefits of using a cross-layering approach. We also describe a first version of the new WiOptiMo based on the innovative design. Results from preliminary tests in real-world scenarios indicate the effectivness of our pragmatic approach. The system is still under development and testing, and we plan to integrate in it several autonomic components, which are presented and discussed in the paper