>I'm not clear on your problem but the rules are simple : Convert to < when the character is to be treated as text rather than an XML start tag.
>
>BTW, why don't you use the one of the .NET xml classes rather than constructing one long string. The XmlDocument, XDocument, or even the basic XmlWrter classes all make the construction of XML cleaner and less error prone. The above could be something like:

XDocument cSoapMessage = new XDocument(new XDeclaration("1.0", "UTF-8", ""));
>            cSoapMessage.Add(new XElement("Envelope",
>                new XElement("Body",
>                    new XElement(cMethod,lcPostData))));

Admittedly I've not included the namespaces which is a little more complicated - but again can prevent xmlns errors down the line.

The reason was so that I have full control over the entire envelope. Specific servers require specific SOAP configuration sometimes and by using that approach, I can see exactly the entire SOAP XML.