B2B data exchange deals often not only with the representation of content in standardized data structures, but also with the transformation of relational data to XML-based data and vice versa. During the transformation process not only the data structures but also the power of the data modeling concepts of the respective document standards must be considered. Based on this knowledge the conversion could be made easier or partly automatically. This paper examines, to what extent real-world B2B data exchange standards make use of XML schema languages for formal specification and if they tap the full potential of these languages. For that purpose the relevant modeling concepts are viewed and applied to selected B2B standards. The result is a close look at the common practice of XML schema languages in B2B data exchange.