This paper describes how XML is used to unify the implementation layers of a problem solving environment WBCSim. WBCSim is a Web based simulation system designed to increase the productivity of wood scientists conducting research on wood-based composites manufacturing processes. WBCSim serves as a prototypical example for the design, construction, and evaluation of small-scale problem solving environments. WBCSim supports five process models. A XML datasheet is tailored for each model. The WBCSim interface layer, server scripts and database management system all use this XML datasheet to improve the usability and maintainability of the three layers--client, server, developer--comprising the WBCSim system. A detailed description of the WBCSim system architecture is presented along with a typical scenario of usage.