online XML editor written in Flash or Flex

I am looking for an online XML editor written in Flash or Flex. I would like to allow me clients to be able to, very easily, edit a variety of XML documents without the possibility of breaking them. The XML that will be edited will be relatively simple - for example an RSS file. But the application will need to be flexible enough to edit a variety of XML documents. I need to be able to load an external XML doc into the app and then edit its contents and node order and then output similar XML back out, ready to be sent to the server. I can handle the server writing. Important Features: Change order of nodes. Edit the attributes and contents of nodes The simpler the interface the better. I would prefer the application written in Actionscript - Flash or Flex but I would consider JavaScript and PHP as well. I will need the rights to resell this application.