1. A method for creating or updating a customization for an Extensible Markup Language (XML) based metadata document, the metadata document defining one or more characteristics of at least a portion of a software application, the method comprising: retrieving the metadata document via a software component configured to enable creation or update of XML documents; receiving, from the software component, one or more modifications to the metadata document, wherein the one or more modifications are expressed using a standard XML update protocol; translating the one or more modifications into one or more customization instructions; and storing the one or more customization instructions as a first customization for the metadata document, wherein the first customization is stored separately from the metadata document.