Data exchange specifications not only must be broad and general to achieve acceptance, but also must be customizable in a controlled and interoperable manner to be useful. The Product Life Cycle Support (PLCS) suite of data exchange specifications (known as DEXs) uses templates to enable controlled customizability without sacrificing breadth or interoperability. DEXs are business context-specific subsets of ISO 10303 Application Protocol (AP) 239, subject to additional constraints imposed by the templates. A PLCS template defines how AP239 entities and their attributes will be instantiated using an externally-defined controlled vocabulary defined in a Reference Data Library. Template instantiations are defined using an Instantiation Path (IP) specified using an arcane syntax that must be manually written by the template developer. The PLCS information model is formally defined in the ISO 10303 EXPRESS language, but there is no formalism used at the template level. A challenge for newcomers to PLCS is to dive into and understand all the bespoken, non-standardized and PLCS-specific technologies (domain-specific languages and software) used to develop and implement the templates. DEXML presents an approach based on the Unified Modeling Language (UML) enabling the use of mainstream software and technologies to develop and implement DEXs, reducing the need for nonstandard and unfamiliar languages and tools.