The document outlines a method for developing extensions to BPMN 2.0, emphasizing the creation of a conceptual domain model and the transformation of this model into a validated XML schema. It introduces a BPMN+x UML profile to facilitate graphical representation of BPMN extensions and includes a description of a tool that supports this method. The proposed approach aims to enhance the usability of BPMN extensions while ensuring compatibility with existing BPMN tools.