How to implement custom JSON serialization from ASP.NET web service?

Question

What options are there for serialization when returning instances of custom classes from a WebService?

We have some classes with a number of child collection class p

Answer 1

Don't quote me on this working for certain, but I believe this is what you are looking for.

[WebMethod]
[ScriptMethod(ResponseFormat = ResponseFormat.Json)]
public XmlDocument GetXmlDocument()
{
    XmlDocument xmlDoc = new XmlDocument();
    xmlDoc.LoadXml(_xmlString);
    return xmlDoc;
}