Soap Header : Adding authentication in Soap message

Question

authentication token in Soap Headers?
How to use this in SOAP message

and

<AuthenticationToken xmlns="....">

What is that 'xmlns'
what should i use or write there 

Answer 1

1. SOAP authentication is not within the scope of a foum. read below article http://msdn.microsoft.com/en-us/library/aa529264.aspx
2. xmlns is XML NameSpace. I hope you are aware of NameSpace in C# as we can even add same named calsses under different NameSpace. In XML too one purpose is that we can have same elements under different xmlns. This avoids elemens name conflict. You can see it's usage here http://www.w3schools.com/Xml/xml_Namespaces.asp