Inserting username/password in soap header using wse

Question

I am creating an asp.net web service using visual studio 2008 using wse3.0. It will be calling a java web service in JBoss WebSphere. The java web service expects username/password token in the soap header.

i have created web service proxy

Dim srv As New externalWebservice.externalWebservice()  
Dim userToken As UsernameToken  
userToken = New UsernameToken("userid", "password", PasswordOption.SendHashed)  

now trying to get the soap context
srv.RequestSoapContext() i dont find the RequestSoapContext i'm i missing some thing here?

Can anybody point me to right direction or some sample codes on how to insert username/password into the soap header of a web service call

Thanks
Vinod