The institutional goals and the organisational contexts of GL producers, determine the level and the process of production and diffusion. Furthermore GL producers do not all bring the same "dowry": they have neither the same resources, nor the same information policy. Inspired by such considerations the Italian reference centre of SIGLE (System of Information on Grey Literature in Europe), has based its activity on the Cupertino with GL producers. To achieve this aim the Centre has evolved from a merely receptive role, consisting of pure and simple acquisition and bibliographic treatment of documents, to an active role, in order to control the very process of document production by exerting a consulting function on bibliographic aspects. In other words is the Centre that places itself at disposal of producers to solve all the problems connected with their participation in the SIGLE database. As an example of this policy the paper describes the interaction between the SIGLE Italian reference centre and the Library of Italian Chamber of Deputies which produces the database LEGO, which stands for Grey Literature Online, containing non commercial, official and administrative documents, produced and/or acquired by the Library since 1993. The consulting activity developed by the centre has allowed a fast and efficient acquisition of the document stored in LEGO. Finally the paper describes the type of documents in LEGO, the selection criteria and the issues connected with information integration.