CREATE TABLE [dbo].[test_table](
	[dt] [datetime] NOT NULL
)
GO
create procedure [dbo].[test_procedure](@dt datetime)
 as
begin
 insert into test_table(dt) values(@dt)
end
GO

//TestDomainService.cs
    [EnableClientAccess()]
    public class TestDomainService : LinqToSqlDomainService<TestModelDataContext>
    {
        public void ExecuteProcedure(DateTime dt)
        {
            DataContext.test_procedure(dt);
        }
    }

//MainPage.xaml.cs
        private void button1_Click(object sender, RoutedEventArgs e)
        {
            TestDomainContext db = new TestDomainContext();
            db.ExecuteProcedure(DateTime.Now);
        }