I have an application that interacts with MSCRM 4.0. When I try
to update the date of birth field on a
contact I get an error message every
time. The error is different every
time I try a new way... 

So the
question is in the context of the
following code how do I update the
BirthDay on the new contact I am about
to create?

```
using System;
using System.Collections.Generic;
using System.ComponentModel;
using System.Data;
using System.Drawing;
using System.Linq;
using System.Text;
using System.Windows.Forms;
using ProjectName.CrmSdk;

//The CrmSdk ref is to the webservice url.

//ServerName and OrgName are setup in code but not included.
//standard CRM service setup
CrmSdk.CrmAuthenticationToken token = new CrmSdk.CrmAuthenticationToken();
token.AuthenticationType = 0; //AD on premise
token.OrganizationName = orgName.ToString();

CrmService service = new CrmService();
service.Url = "http://" + serverName.ToString() + "/mscrmservices/2007/crmservice.asmx";
service.CrmAuthenticationTokenValue = token;
service.Credentials = System.Net.CredentialCache.DefaultCredentials;

DateTime dt = new DateTime();

// set the date time to some date...
contact c = new contact();

c.firstname = "joe";
c.lastname = "Smack";
c.BirthDay = dt.ToString();

```