I recall long time ago one of the selling points was to take a trojan and pack it, zip it rar it and use TDS-3 and it will still find it. I just discovered that it's not true. I have X-rat and delerium of disorder which are ziped and then rared and when I scan them through right click context menu I had nothing. When I unpack them and just scan the first packed file I get positive ID. So this means that I can double pack a trojan and it will evade TDS-3?