Dynamism of mobile ad-hoc networks implies changing trust relationships among their nodes that can be established using peer-to-peer PKIs. Here, certification paths can be built although part of the infrastructure is temporarily unreachable because there can be multiple paths between two entities but certification path discovery is difficult since all the options do not lead to the target entity. On the contrary, in hierarchical PKIs, there is only one path between two entities and certification paths are easy to find. For that reason, we propose a protocol that establishes a virtual hierarchy in a peer-to-peer PKI. The results show that this protocol can be executed in a short time. In addition, our protocol does not require to issue new certificates among PKI entities, facilitates the certification path discovery process and the maximum path length can be adapted to the characteristics of users with limited processing and storage capacity.