Providing interactive mockups of mobile applications in designing phases introduces new challenges for interaction designers compared to the traditional way of static mockups. In particular, the complexity of this process increases when it comes to enabling the user to actually explore the intended user experience of the mobile environment by enhancing traditional handmade sketches or tool-generated wireframes with concrete mobile interaction elements. We introduce a framework, called i2ME (interactive Mockup-Building for Mobile Environment), for building interactive mockups with concrete mobile interaction elements. The framework enhances the static mockups (handmade or tool-generated) with screen transitions and multi-touch gestures, and enables the deployment of the resulting HTML5+JavaScript based interactive mockups to multiple platforms and device classes.