Implement a data service call in a Silverlight application

I have a Silverlight web application with a view, containing a pop-up with four textboxes on it, a submit button and a cancel button. The application is otherwise complete and operational, and has an existing data service. So I need someone to investigate and understand how the application is working, then link the Submit button to an already-written stored procedure, passing those text-boxes in as input parameters, and displaying a MessageBox with a single-cell recordset result from that SP.

Another developer wrote the application up to this point, but I no longer have access to him. I've tried to write this modification myself, but have failed since I'm simply not a silverlight developer - I'm a SQL developer. I've got the pop-up appearing how I want it, with the boxes as I want (Old Password, New Password, Confirm new password, Password Reminder). The content of the Password boxes need to have an encryption algorithm applied to them - there is a working example of this on the New User Signup page.

Once working, I need to know what objects you wrote because this needs to be repeated in an identical fashion on two other SL views.

You will be provided with public RDP access to the deployment server with Visual Studio 2010 Professional installed and running on a development instance of the code.

I expect relatively fast work - there should be enough precedence set within the existing application to be able to replicate these methods for this simple database call - probably an hour to get a feeling for the app and an hour to write the data service call.