Hi, I short you will need a database or other persistence for holding
the users' ids and password for validating against.
Next, you can create your webservice in the language of your choice
but I will use ruby in my explaination. This webservice will either
communicate to your persistent entities using Rails AR or the Ruby
Now, you will create a standalone SOAP server that regsiters your
webservice. See Page 249 of "Programming Ruby" for more detail.
Finally, you should be able to refactor existing authetication schemes
to easily use your web service.