1. A system to facilitate the definition of a composite web service configured to support application flow and processing using a plurality of mainframe applications via a single simple object access protocol request, the composite web service providing access to multiple applications in a single web service by combining functions from the plurality of mainframe applications, the system comprising a system data store and a system processor and further comprising: a modeler configured to interface with a user to enable the user to generate an application flow, the modeler including a graphical interface for building the application flow and data movements between the plurality of mainframe applications, the modeler creating one or more flow rules, generated as instructions in web services description language, to build the composite web service, wherein the modeler enables the user to define functionality required from the plurality of mainframe applications to be provided in the composite web service, wherein the composite web service includes at least one call to a mainframe application, and wherein the application flow is formed by a plurality of connected graphical objects and the application flow through various nodes controls logic processing for the plurality of mainframe applications which provide the user-defined composite web service functionality, and wherein the modeler includes a debugger configured to: receive user-defined inputs and expected outputs for processing of the flow rules via the graphical interface, wherein the user-defined inputs and expected outputs are defined by each node and the web services description language instructions are created from properties entered into the graphical interface by the user, step through the flow rules, wherein the step through includes at least one call to a mainframe application, trace results of the step through, provide the trace results to the user via the graphical interface, and verify syntax of those flow rules that control execution of the plurality of mainframe applications by tracing a logic path for a connection included in the application flow to ensure a correct flow is processed by a requested web service operation, wherein syntax is verified each time a node connection is attempted to ensure a valid logic path and that node connection rules are correct; and a manager configured to parse the flow rules to generate a programmatic implementation of the composite web service for execution on a web services server, wherein the modeler is configured to utilize the debugger to verify the one or more flow rules of the composite web service by checking properties and connections between the nodes to ensure the flow rules are complete and valid prior to the modeler deploying the flow rules to the manager for generation of the programmatic implementation of the composite web service for execution on the web services server.