If I'm not wrong the internet is currently being flooded with variants of this malware. This would make it very difficult to detect all of them.
I can confirm that Comodo detects many of them, but no AV can ever detect all.
If you find that you have an undetected malware on your computer please submit it to:http://internetsecurity.comodo.com/submit.php
so that the entire community can be protected from it.