Multi Level Modeling (MLM) has been around in the modeling community for over twenty years. It has attracted much attention, both on theoretical and practical grounds. Multiple approaches have emerged, with different support for MLM concepts on the levels of syntax, semantics and pragmatics. MLM tools support a variety of applications, ranging from ontology specification to software modeling. This paper introduces the MedMLM-USE tool, which implements the Mediation-based MLM theory as an extension of the USE tool. The USE tool has been selected due to its open, well-structured architecture. The MedMLM-USE application extends: (1) the well-defined meta-model that is supported by USE, with MedMLM concepts; (2) the USE modeling services to support MLM-models. This paper describes the extended meta-model and services, provides examples, defines an inheritance semantics for instance-of, and discusses engineering difficulties.