Model-Driven Engineering (MDE) encourages the use of graphical modeling tools, which facilitate the development process from modeling to coding. Such tools can be designed using the MDE approach into metamodeling environments called metaCASE tools. It turned out that current metaCASE tools still require, in most cases, manual programming to build full tool support for the modeling language, especially for users' native methodologies and representational elements and suffer from gaps in terms of reusability. In this context, we propose MID, a set of metamodels supporting the specification of modeling editors by means of reusable components and explain how representational metamodeling is carried out with it.