The system we will demonstrate was built as part of a research in generation of simulation models for a restricted class of ecological domain. A model generated by our tool is a Prolog program used to evaluate population behaviour in a eco-system. We used "Prolog programming techniques" and "Prolog schemata" as the elements of program construction. One can have a good idea of an ecological model's main parameters and the final shape it should have, but often s/he doesn't know how to put all together in a neat piece of code in some programming language. That happens because modelling is not a straightforward task, it certainly has a lot of expertise embedded and it is often done in a non-structured way, leading to results not always as expected. This is specially evident if s/he is a novice modeller and/or have little or no knowledge of programming. Our "simulation model synthesiser" leads the user through a series of decisions and specifications about the model and uses that knowledge to guide a structured techniques-editing based program generation.