*Abstract*: Plug-in components are a means for making feature-rich applications customizable. Combined with plug-and-play composition, end users can assemble customized applications without programming. If plug-and-play composition is also dynamic, applications can be reconfigured on the fly to load only components the user needs for his current work. We have created Plux.NET, a plug-in framework that supports dynamic plug-and-play composition. The basis for plug-and-play in Plux is the composer which replaces programmatic composition by automatic composition. Components just specify their requirements and provisions using metadata. The composer then assembles the components based on that metadata by matching requirements and provisions. When the composer needs to reuse general-purpose components in different parts of an application, the component model requires genericity. The composer depends on metadata that specify which components should be connected and for general-purpose components those metadata need to be different on each reuse. We present an approach for generic plug-ins with component templates and an implementation for Plux. The general-purpose components become templates and the templates get parameterized when they are composed.