The purpose of the XML Key Management Specification (XKMS) is to facilitate the use of a Public Key Infrastructure (PKI) by transferring the complexity associated with PKI to a trusted Web Service. Although this specification contains information on how compatibility with PKIs such as PGP and SPKI/SDSI can be reached, it is straight focused on X.509 PKI. This work uses XKMS to define a federated management model for SPKI/SDSI. In a web of SPKI Federations, the proposed model follows a peer-to-peer approach for discovering and establishing certificate chains. This model introduces a search algorithm and its effectiveness was verified through simulations.