As i said above, if you are using the eWay credit card web service then you won't be able to authenticate the user credentials unless you write your own VB Script task.
SSIS 2005 Web Service tasks do not allow proper login authentication credentials to be entered.
SSIS 2008 does this, but it still does not support complex types. However you can do it as a VB script task real easy. I also created a web service to debug my vb scripts and to help make a better wsdl file.
If anyone would like to ask me question about how to do all this with a very complex custom types and classes web service send me a private message. The service I had to do this for recently even had a custom date class that was part of a custom array of items class.