if you're using pes2009 v1.2 you can use kitserver and Pro Evo Editing Studio v1.4 to give your player a decent face using the import face / hair option.
I guess soon you'll be able to do it with pes2009 1.4 as the editing studio will support the 1.4 game version in the near future, and there's a new kitserver-ish prog in the makings called pes2009plus v1.4.10 wich is really good.
When this happens, then custom faces in BAL will be very easy to do.
It is probably possible to do it without a kitserver aswell, but then you will need to implement the custom face into the .img files yourself and I haven't figured out how to do that properly yet.
Those who know how to haven't spilled the secret to me yet
Relinking a BAL player to an already existing face in the game is possible without any kitserver or pes2009plus, but having identical twins in the game isn't that facinating for me at least.