Sandboxed CRM Plugin File Handling

Hello All

I have a plugin that creates an XML file based on some fetchxml results. However since this is a plugin for CRM Online, it is sandboxed and obviously I am getting an error when I attempt a save on local drive through the code. One of the options I have come to know is to write a web service that consumes the InnerXML and creates a file in the server. Is there any other neat way to do this which is less prone to a number of points of failure? 

string _fetchXmlOutput = _xml.OuterXml;
StringReader _xmlst = new StringReader(_fetchXmlOutput);
XmlDocument _xDoc = new XmlDocument();
_xDoc.LoadXml(_fetchXmlOutput.ToString());
_xDoc.Save(@"C:\outputxml\" + DateTime.Now.ToString("yyyyMMddHHmmss") + ".xml"); //--To be replaced.

Cheers,

Kush