Active Directory - Creating user with C# (no userPrincipalName)

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C#

Hi!
I don't know why, but creating user in AD gives me a user without "userPrincipalName".
I do it with the folowing code:

using (DirectoryEntry companyEntry = companysDir.Children.Find("OU=" + companyName))
{
    DirectoryEntry newUser = companyEntry.Children.Add("CN=" + login, ADobj.User);
    newUser.Properties["samAccountName"].Value = login;
    newUser.CommitChanges();
    if (password != null)
    {
      newUser.Invoke("SetPassword", new object[] { password });
      newUser.CommitChanges();
    }
    newUser.Close()
}

The result is look like that:

<img src="http://s1.ipicture.ru/uploads/20120523/R02782Su.jpg">

And ofcourse user disabled. Why is this happens?