Portal 1 cube replacement for Portal 2 file

First you make a shortcut of the vpk from the portal 2 bin and then you drag the file to the shortcut and it makes a vpk.Second you have to copy the file and paste it in the portal 2 bin and do the same thing and when you've done that it would appear like this ( pak01dir ) change that into ( pak01_dir ) and run the game and enjoy :)