Guys, I HAVE FINISHED THE PROGRAM!!!
I have only to write a little documentation and tomorrow morning I will give you the download link
Here you are two screen to show you an example of the potentiality of the tool:
You can see that I have created the Japanese league (random teams), letting the program create 4 new teams for me (with the range of id in the tables I previously created). Then, in the second screen you can see the right assignation of players (with their id) I had assigned to the team with the program and the creation of the missing players until reaching the number of players per team chosen (23), always respecting the range of id chosen for japanese league!
You can already see how much is important to keep original id: Thiago Neves has his own miniface in the game
Maybe you don't figure out all the options, that's why I'm going to write a little and useful "how to use" list. Just a first hint: the "Show all teams" checkbox in the leagues group box is made to show you, in the "already existent teams" all the teams that are in the list I made. In this way you can be sure that the team is not in the list before creating it from a Japan_1 (or Japan_2, Japan_3, Japan_4) team. Why did I make this?
Mainly because the team-league assignation of fifamanager10 list I have is not updated. So, if I kept only the normal checkedlistbox based upon your chosen league, you could have lost some teams that were present in the second division league, for example. In this way (showing all teams), you can use the search function and find out if really the team does not have already an id assigned by EA SPORTS or not!