In Inazuma Eleven 3 (all versions: Spark, Bomber and Ogre) to recruit players from Inazuma Eleven 1 teams you have to use mobile passwords. Here's a step by step guide:
1) Check your save file name, it's written here.
2) Write it in the following textbox (you can use an on-line keyboard like this one).
3) Click on "Generate" to print a list of passwords for all players.
4) Insert the password here to recruit your player.