2009 Navision sp1 Web Service and ASP.NET (How do I pass the security account?)

dear all:

I need to get “WEB Service”,But How do I pass the security account?

System.Net.CredentialCache.DefaultNetworkCredentials.Domain = “ChihmingDomain”;
System.Net.CredentialCache.DefaultNetworkCredentials.UserName = “XXXXXXX”;
System.Net.CredentialCache.DefaultNetworkCredentials.Password = “XXXXXX”;
WebServiceURL = “http://10.103.37.5:7047/DynamicsNAV/WS/CRONUS%20International%20Ltd/Page/Item”;
this.ItemCardService.Credentials = CredentialCache.DefaultNetworkCredentials;

this.ItemCardService.Url = WebServiceURL;
this.ItemCardService.UseDefaultCredentials = true;

[:D]