One and the same inter-organizational business process - such as e-procurement - may be executed differently in different industries, geopolitical regions, etc. Thus, a standardized reference model for inter-organizational business processes must be customized to the specific business context (industry, region, etc.). In order to share, search, and (partially) re-use context specific adaptations it is essential not only to store the adaptations, but also a business context model where these adaptations are valid. In this paper we describe the Unified Context Model (UCM) introduced by the United Nations Centre for Trade Facilitation and Electronic Business (UN/CEFACT). We explain the shortcomings of the approach and show how these can be undermined by our Enhanced Unified Context Model (E-UCM). The enhanced model serves as a basis for contextualizing business documents which are exchanged between different inter-organizational business processes. Having such an approach at hand, helps prevent negative trends in today’s business, such as interoperability issues, inconsistencies and heterogeneous interpretations of the exchanged data contents.