The Italian approach to e-Government is based on the development and deployment of the Unitary Network, a "secure Intranet" interconnecting all the public administrations. The Cooperative Architecture, currently designed on top of it, is the reference distributed computing model in which each administration is represented as a Domain, exchanging data and application services with the others through Cooperative Gateways. Some issues have been, and currently need to be, addressed, such as the presence of legacy systems, the need of a cooperative development process, the identification of the more effective cooperative approaches. In this paper some first experimental projects carried out in the years 1998-2000, aiming at validating the Cooper...