At FOI in Linköping duel simulations are performed between threat systems and the Swedish Armed Forces platforms. The simulation results are used as decision support for programming counter measure libraries, choosing parameters for dispensing chaffs or flares, for education etc. Since the mid 90's, the commercial tool ACSL is used as a development tool for simulation models at FOI. In 2006, a comparative evaluation was performed, due to the release of a new version of ACSL called AcslXtreme that will require a substantial effort in converting simulation models. The evaluation was performed to decide whether AcslXtreme should be used in the future or if there was reason to change the simulation environment entirely. The comparison showed that the main competitor was MATLAB Simulink, and that a number of benefits in changing the simulation environment could be found. The previous work has been resumed during the year. The evaluation of MATLAB Simulink has continued, this time with the emphasis to find general guidelines for the upcoming conversion task. Furthermore, proprietary tools developed at FOI have been upgraded to handle the change of simulation environment. The report describes the work carried out during the year, analysis of relevant model technical characteristics, identified recommendations for future work on converting existing models and suggestions to continued work. The conversion of the models is expected to continue for some years.