What you will need (Other than your External USB drive)
split4g.exe - http://www.ps3news.com/forums/attach...chmentid=22194
MultiMAN Manager/Open Manager
Step 1 -
Step 2 - Open your preferred Manager (I'm going to use MultiMAN Manager)
Step 3 - Copy your split game from your External drive to the PS3s Internal drive
(The split files will automatically join during this process)
Note: If you have Multiman 2.00.01+ You can now play Split games from your external HDD and even use BD mirror/Direct Boot no need to transfer it to your Internal HDD.
Step 4 - Run the game and hope it works.