Problem in inserting data using Silverlight

[dot_net_help]

Hell to every body on Vbforums,
By using Follwoing code i tried to insert data in database in silverlight

 Service1Client webservice = new Service1Client();
            //ServiceReference1Client  webservice = new ();
            bool b;
            b = webservice.InsertVoteAsync ("Abc", DateTime.Now.Date);

and the service code is

[OperationContract]
        public bool InsertVote1(String vote, DateTime  dt) 
       { 
           bool Inserted = false;
           Conn = new SqlConnection("Data Source=xyz-PC;Initial Catalog=Voting;User Id=sa;Password=sa;Integrated Security=SSPI"); 
           Cmd = new SqlCommand(); 
           Conn.Open(); 
           Cmd.Connection = Conn; 
           Cmd.CommandText = "insert into votes values(vote,dt)" ;


           int ins = Cmd.ExecuteNonQuery(); 
           if (ins > 0) 
           { 
               Inserted = true; 
           } 

           Conn.Close(); 
           return Inserted; 
       }

but gives me these errors


Error 1 The best overloaded method match for 'VotingPanel.ServiceReference1.Service1Client.InsertVoteAsync(System.DateTime, string)' has some invalid arguments ........................



Error 2 Argument '1': cannot convert from 'string' to 'System.DateTime' ...............................


Error 3 Argument '2': cannot convert from 'System.DateTime' to 'string'


any one can help me

[dot_net_help]

i added following lines of code too

  private void   InsertVoteCompleted(Object sender,  System.ComponentModel.AsyncCompletedEventArgs e)
    {
      // lblMsg.Text = "Added Successfully!" ;

    }

but did not find the solution uptill now