The purpose of this project has been to build up knowledge about how future Mixed-Reality (MR) systems should be designed concerning technical solutions, aspects of Human-Machine-Interaction (HMI) and logistics. Two MR-systems have been developed, one biocular and one gaze-controlled monocular. The MR-systems consist principally of a head-mounted micro-display-system, an integrated image sensor for indirect vision, an integrated gaze-tracker, a computer and software for MR and a tool for flexible composition of application examples For real-world positioning the MR-system uses marker detection. Each marker is linked to some form of virtual image information which is mixed into the image from the image sensor. To illustrate which HMI aspects that are related to the use of an MR-system for technical support, a comprehensive literature search and survey of knowledge have been carried out. This work has resulted into a theoretical frame work that is described in the report. To further illustrate HMI aspects a number of practical tests with prototypical equipment have been made. A relevant application example, dismounting of a machine gun mounting, has been performed and evaluated. The goal concerning the application example was to demonstrate how an MR system could work as a help for assistance during technical support.