As you're a french native, there's a tutorial from Sonic131st :
Basically, just add your markpoints, switch the flight plan to Markpoint, and to drop the bomb just set your SPI to SPT and drop your bomb, switch to the other mkpoint, drop the bomb and so on.
http://forums.eagle.ru/showpost.php?p=1344603&postcount=2
I found the post from Viper, it's pretty easy to understand the concept! Have fun.