System.Func Converter Challenge

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C#3.5

Ok. Here's the scenario. You have a domain model in which all the entities inherit the IEntity interface. This would force your application to use the same name for ID throughout the application. This is fine for the application but since we cannot force the rest of the world in the same pattern. It would be cool to be able to query entities and be able to map to other types with the same query without worrying the backend implementation

Maybe some code example would be in order:

namespace FuncTypeMapper
{
    public class User : IEntity
    {
        public int ID { get; set; }
    }
    public class DbUser
    {
        public int userId { get; set; }
    }
    class Program
    {
        static void Main(string[] args)
        {
            // Trying to get a user with ID 3
            Func<User, bool> entityQuery = u => u.ID == 3;

            // However, the Linq type for user account don't contain property
            // ID for user, it has userId instead
            // so we need to convert the System.Func into DB compatible query
            Func<Func<User, bool>, Func<DbUser, bool>> queryConverter = f => f.????????????;
            // How to solve the above with C#???

            // Then we could just convert the query
            Func<DbUser, bool> dbQuery = queryConverter.Invoke(entityQuery);

            // Before we Invoke it against the database
            var usersFromDb = from u in dc.UserAccounts
                              where dbQuery.Invoke(u)
                              select u;
        }
    }
}

I do know of Entity Framework Code First pattern and I've been looking into other solutions also, so that is not what I am looking for. I am looking for using C# features and hand mapping between the types whether they'd be Linq to SQL classes, Web Service types or whatever that stores data in a class.