Collaboration in a business system requires a business process specification defining the procedure of the business scenario. The business process specification is generated from a business process model. ebXML, which is the XML-based B2B standard framework for organizations of any size using the Internet, recommends process analysts and modelers to use the UN/CEFACT Modeling Methodology (UMM). The artifacts of the modeling are UML diagrams and worksheets. They can be transformed into an ebXML Business Process (BP) specification and other business models. The artifacts and transformed results are registered in the business library for being shared with ebXML systems and being re-used in other modeling tools.This paper reports on our implementation of an ebXML BP modeling toolkit that accepts the architecture suggested in the ebXML and considers the required functions of modeling. These functions include modeling business processes based on UMM, generating a BP specification, transforming the processes using a metaframework, and registering them in the ebXML registry. The business process modeling toolkit is made up of the business process modeler, business process editor, and built-in registry client. The business process modeler not only models the business process with UML diagrams but also generates the business process specification, reverses it, and exports XMI of the business process. The business process editor is used only for editing the business process specification. The built-in registry client stores the business process model, the business process specification, or the XMI document, and searches and loads them.