Pass additional parameter to SOAP header?

We are using webservice datawindows to pass request xmls to call webservices. Additionally we use 'wsconnection' objects authenticationmode, username and password property to send information to SOAP header.

Now we have to send one more value to SOAP header. This new value will be a string(like username).

I checked the wsConnection properties and did not find anything which could be used. Can anyone please advise on it.