This document demonstrates a possibility for extension of the LYEE methodology by using the Enterprise Modelling approach. The Karlstad University unit undertook the work. The major contribution of this report from the practical point of view is to illustrate by various examples how enterprise modelling approach can contribute in the phase of system requirements engineering in the context of LYEE. The overall investigation is based on examples of a real case study in the area of e-commerce. Most software methodologies are heavily centred on system development issues at the implementation level. Thus, such methodologies are restrictive in a way that a supporting technical system specification can not be motivated or justified in the context of organisational process models. A blueprint of enterprise infrastructure provides a basis for the organisations information technology planning. It is sometimes referred as enterprise architecture. The major theoretical effort of this report is to demonstrate the Lyee software engineering methodology extensions by using the enterprise modelling approach. The main focus is on the issue of the pragmatic, semantic and logical software requirements integration by using the enterprise models.