Customization of National Team`s members

I found that some non-official national teams, like Japan, its squad `s not correct or got 2 players with the same name...Is it possible to select and change some National Team `s players by my own-self?? What tool should I use?

It seems that `Transfer` can not be used to achieve this...

Please give advice.

The Japan national team is "broken" because of licensing issues. There's no way of fixing it, other than downloading a custom database.

I watched a video which shows once there is an editor called IGE, one can change the player`s name & attribute in the game easily. But where can I get this?? Not for free?