The Situational Method Engineering (SME) discipline emerged two decades ago to face up to the challenge of the in-house definition of software production methods and the construction of the corresponding supporting tools. However, nowadays most of the existent proposals only focus on one of the phases of the SME lifecycle. In order to fill this gap, in this paper we present a methodological framework that equally encompasses two of these phases, which refer to the method design and implementation. In order to support them in an effective manner, we advocate for the use of the Model Driven Development (MDD) paradigm. Applying these ideas, the framework has been defined on top of a MDD infrastructure based on meta-modeling and model transformation techniques. In addition, we provide implementation details of the framework in an Eclipse-based modeling platform, namely MOSKitt.