How to write SoapClient request which has basic auth in it?
I believe the answer is nearly there for you, but ID and credential are the wrong keys in the options array.

       'login' =&gt; 'USERNAME',
       'password' =&gt; 'Password',


I suggest that you put the username and password into conf in your settings.php file so they are not in your codebase nor your site configuration data. See How secure are variable_get and variable_set? for details on how to securely have credentials in Drupal's config system.