One promising solution for meeting the demands of constantly-evolving Real-Time Embedded (RTE) software is the model-driven development (MDD) paradigm, based on the principle of separating the description of an application from its platform-specific implementation. Existing model-driven approaches strive to achieve this separation through dedicated model transformations which actually embed a given computing platform model. This is a major impediment for MDD dissemination in an industrial context. The resulting dearth of customizable transformations hampers description of reusable generative processes. We therefore propose to explicitly describe the targeted computing platforms in the design process. The main benefit expected from explicit platform models is a true separation of concerns that enables efficient, reusable and customizable generative processes. This proposal is strongly promoted by the new OMG (Object Management Group) standard profile for Modeling and Analysis of Real-Time and Embedded systems (MARTE), with its software multitasking platforms. In this paper, we first describe the MARTE feature and then propose a framework for integrating explicit platform descriptions into a model-based generative process.