The problem is more difficult because there are TWO "New" options in CRM 2013:
Onclick of lookup img you get this options:
http :// i.piccy.info/i8/ccdbcf0520b93e07d18739408c4f19be/1382013984/7530/632712/lookup1.png
And if you click on "Look Up More Records" you get this:
http ://i.piccy.info/i8/87761d6af244e1b04f9b49e5167b3f74/1382014069/22102/632712/lookup2.png