Cloud Computing and federation enable new challenging business scenarios. However, the technology driving federation is at the early stage and many issues have to be overcome. On one hand, an important problem is how to logically map the virtual resources hosted in federated cloud data-centers. On the other hand, another issue consists of how to exchange data in a secure way to enable a cloud to access only the allowed external resources. In this paper, we address both issues adopting the concept of ‘Dataweb’’ and the XDI technology. More specifically, using the Higgings framework an use case including several IaaS federated clouds is discussed and evaluated, specifically focusing on security.