This Weblog introduces you how to connect to XI server from a webdynpro
The First few steps are very familiar ::
Just create a project and an application, then create a view with the UI elements that are required.This explains how to pass the Username and Password to the XI server in a XML format.
So you have Username and password as textbox UI elements on your view and corresponding context value attributes of type string.
String urlString = "";
String str= "
encoding="UTF-8"?>
"
"<ns1:httpMT xmlns:ns1="urn:xitraning:rms">
"""userid"</userid>
""<password>"pwd"</password>
""
Thus the retrieved values will be present in your "result" String which you can parse and do the further processing's.