I've followed the instructions of Mac's answer here and I've built my own custom extension:
public static class HtmlHelperExtensions
{
    public static string HtmlIdNameFor<TModel, TValue>(
        this HtmlHelper<TModel> htmlHelper,
        System.Linq.Expressions.Expression<Func<TModel, TValue>> expression)
    {
        return (GetHtmlIdNameFor(expression));
    }
    private static string GetHtmlIdNameFor<TModel, TValue>(Expression<Func<TModel, TValue>> expression)
    {
        if (expression.Body.NodeType == ExpressionType.Call)
        {
            var methodCallExpression = (MethodCallExpression)expression.Body;
            string name = GetHtmlIdNameFor(methodCallExpression);
            return name.Substring(expression.Parameters[0].Name.Length + 1).Replace('.', '_');
        }
        return expression.Body.ToString().Substring(expression.Parameters[0].Name.Length + 1).Replace('.', '_');
    }
    private static string GetHtmlIdNameFor(MethodCallExpression expression)
    {
        var methodCallExpression = expression.Object as MethodCallExpression;
        if (methodCallExpression != null)
        {
            return GetHtmlIdNameFor(methodCallExpression);
        }
        return expression.Object.ToString();
    }
}
I've imported my application's namespace
<%@ Import Namespace="MvcApplication2" %>
and finally I can use my code like this:
<%=Html.HtmlIdNameFor(m=>m.Customer.Name)%>