This paper presents a feasibility study for implementing lexical morphology principles in a machine translation system in order to solve unknown words. Multilingual symbolic treatment of word-formation is seducing but requires an in-depth analysis of every step that has to be performed. The construction of a prototype is firstly presented, highlighting the methodological issues of such approach. Secondly, an evaluation is performed on a large set of data, showing the benefits and the limits of such approach. .