Model inference methods are attracting increased attention from industrials and researchers since they can be used to generate models for software comprehension, for test case generation, or for helping devise a complete model (or documentation). In this context, this paper presents an original inference model approach which recovers models from Web application HTTP traces. This approach combines formal model inference with domain-driven expert systems. Our framework, whose purpose is to simulate this human behaviour, is composed of inference rules, translating the domain expert knowledge, organised into layers. Each yields partial IOSTSs (Input Output Symbolic Transition System), which become more and more abstract and intelligible.