How do i pass xml file to restful wcf

Question

Hi i am developing a restful webservice in wcf. i have created a method in service file which takes a vuser(entity class) and process it and register that the user. The requirement is to send the vuser in xml format to the creatuser method. my question is how do i send the vuser to test my method in the xml format to the uri.Please help me.Thank you.

namespace Authentication
{
    [ServiceBehavior(InstanceContextMode = InstanceContextMode.Single, ConcurrencyMode = ConcurrencyMode.Single)]
    [AspNetCompatibilityRequirements(RequirementsMode = AspNetCompatibilityRequirementsMode.Allowed)]
    public class Authenticate : IAuthenticate
    {

        #region IAuthenticate members
        public string CreateUser(VUser user)
        {
            if (user == null)
            {


            }



        }


namespace Authentication
{
    [ServiceContract]
    public interface IAuthenticate
    {
        [OperationContract]
        [WebInvoke(Method = "POST", UriTemplate = AuthenticateUriTemplate.CreateUser)]
        string CreateUser(VUser user);

        //[OperationContract]
        //[WebInvoke(Method = "POST", UriTemplate = AuthenticateUriTemplate.Login)]
        //string Login(string userid,string password);

        //[OperationContract]
        //[WebGet]
        //void Logout(string AuthToken);

        //[OperationContract]
        //[WebInvoke(Method="PUT", UriTemplate=BlogUriTemplates.AdminPost)]
        //string ChangePassword(string AuthToken,string oldPassword, string newPassword);

        //[OperationContract]
        //[WebGet]
        //string RetrievePassword(string AuthToken, string emailid);

    }
}


        #endregion IAuthenticate
    }
}