Most of modern constraint modeling languages combine rich constraint languages with mathematical notations to tackle combinato- rial optimization problems. Our purpose is to introduce new component- oriented language constructs to manipulate hierarchical problems, for instance for modeling engineering system architectures with conditional sub-problems. To this end, an object-oriented modeling language is as- sociated with a powerful constraint language. It offers the possibility of defining conditional components to be activated at solving time, declar- ing polymorphic components whose concrete types have to be deter- mined, and overriding model elements. We illustrate the benefits of this new approach in the modeling process of a difficult embodiment design problem having several architectural alternatives.