1. A method for facilitating the reuse of logic implemented in an existing software application, the method comprising: receiving, at a computer system, a selection of an existing software application, wherein the existing software application is built using an application technology that is not Web service-enabled; generating, by the computer system, metadata based on data parsed from program code for the existing software application; receiving, at the computer system, one or more customizations to be applied to the metadata; modifying, by the computer system, the metadata based on the one or more customizations; and generating, by the computer system, artifacts for a Web service based on the modified metadata, the Web service being configured to expose a Web service operation that, when executed, causes an existing operation implemented in the existing software application to be executed, wherein the generating the artifacts for the Web service based on the modified metadata comprises: generating a mapping file identifying the existing operation, its associated data objects, and a mapping between the existing operation and an alternative operation name; and generating a template payload file defining a template payload to be transmitted to the existing software application at a time of invocation of the Web service operation, the template payload including an invocation of the existing operation, one or more placeholder values for one or more input parameters, and a sequence of zero or more sub-operations to be executed by the existing software application in order to carry out the existing operation.