Dim Message As String = String.Empty
Dim TargetUserName = String.Empty  'but could be "seller1" or "seller2"
 
Dim credentials As UserIdPasswordType = New UserIdPasswordType
credentials.Username = "master1"
credentials.Password = "master1password"
credentials.Signature = "master1signature"
If Not String.IsNullOrEmpty(TargetUserName) Then credentials.Subject = TargetUserName
 
Dim customSecurityHeader As CustomSecurityHeaderType = New CustomSecurityHeaderType