XML Schema or DTD management and development tools

1

I was wondering if people could provide me with some suggestions as to tools they use to manage and develop their XML Schemas and/or DTDs to support their webMethods Record structures. I’ve looked at a couple products like XML Spy from Altova and TurboXML from Tibco. We are looking to use these tools to develop internal transaction/document standards for our A2A intergrations.