Cooperative information systems are characterized by distribution, high heterogeneity and scale. Therefore they require interoperable, dependable services on top of which the development of cooperative application can take place. This paper studies, in the context of the Unitary Network of the Italian Public Administration, the problem of increasing the availability of the services exported by a cooperating entity through interoperable middleware. In particular we show how a Fault Tolerant CORBA compliant system, namely the Interoperable Replication Logic (IRL), can be used to increase such availability by building a replicated cooperative gateway that wraps enterprise cooperative applications.