This paper presents a part of an approach of implementing knowledge management within small and medium sized enterprises (SMEs). This approach proceeds iteratively (proposal for a solution, experience feedback, improvement) and takes place within an industrial partner's calculation office. A first part of this work consisted in the proposal of a knowledge management system (KALIS) that can meet the calculation office requirements. The main assumption of the approach is that intensive collaboration between engineers will support knowledge sharing, thus increasing the efficiency of the calculation projects. The paper investigates integration and acceptance issues of knowledge management systems. A litterature review points out that the main barriers are the codification costs, the integration of the system within engineering activities and the management of quality regarding the content of knowledge management system. Then, propositions are given to overcome these barriers in the form of a progressive knowledge formalisation based on collaboration between engineers. The way of integrating KALIS within the activities of the company is also an important aspect of the effective acceptance. Finally, a feedback of the KALIS use within the company leads to propose the firsts steps towards a maturity assessment framework facing the quality improvement issue of the system' content.