i'm asuming that you own the north america verision of winning eleven 7 international, so hopefully you'll find this helpful. You problably encountered yourself that you can't pick an "unregistered" player on the (Second Team) screen. When ever you're in the free transfers screen, if you are trying to transfer a player that is whithin the first 15 players, then you need to send him all the way to the bottom just to make sure is going to work. Say you need to move Lehman from Borussia Dortmunt to Arsenal which I guess you are. Since Lehman is whithin the first 15 players on the team, highlight him and then instead of sending him straight to Arsenal, for the (Second Team) choose Borussia Dortmund again, and switch him with the last player on Borussia Dortmund, this way you don't need to sacrifice one of the real players. All you just did was send Lehman to the bottom to aboid sacrifising. After that the (Second Team) screen will disapear. Now on the (First team) screen, go to the bottom of Borussia Dortmund, and now Lehman is in the bottom of the list, highlight him, and on the (second team) screen go to Arsenal and go to the bottom of the list, and you can now see that you can transfer Lehman with an "unregistered" player from Arsenal, switch him! Again all the stuff I made you do at the beginning was to aboid switching a real player with a real player. And hopefully it worked for you too.
You problably didn't understand me but if you need more help just ask me what part you did not understand, and I'll reply as soon as possible. I had the same trouble at the beginning, but i figured it out.
Oh, I recomend you to also buy the stragedy setup thing, I know is is $3000 WEN, but an easy way is to win either the European Cup or the America Cup, they'll give you $2000 WEN for each of them, The KONAMI Cup won't give you anything, this thing will help you put the new players into their new clubs.
A good place to find the new transfers that were not included on Winning Eleven 7 International:
http://soccerlibrary.free.fr/squads/overview/squads.html
I wish I could sell my setups and transfers from my memory card because I have everything up to date, uniforms, lineups, formations, and everything, but I don't know how to so it.
Hope this will help you.