Minor modify Customer registration functionality Register Page (Developer question)

Hi Developers

I am working on a functionality change for our company's nopcommerce website (version 1.0) . What we want is when a user unselects "I would like to receive newsletters" at Register.aspx page, we want to change our CRM system setting. I am looking the code where the nopcommerce store the data in the nopcommerce database so i can do something there.

I go as far as find this:

<asp:Button ID="StepNextButton" runat="server" CommandName="MoveNext" Text="<% $NopResources:Account.RegisterNextStepButton %>"
                                ValidationGroup="CreateUserForm" CssClass="registernextstepbutton" />

as CustomerRegister.ascx page.

But i can't find the actual code to store the registration data. It should be something like UserRegistrationInsertToDatabase( data) ???

Please help, which page contains those information

Thank You Very Much for Your Help and sorry if "General Support" is not the right location for this type question.

No one knows?? please help.

I am in the same boat.  I am trying to add a dropdown and store it in the database.  Can't find where the storing as actually done.  V1.9