In the teamgear.dbf there is a field for 'SHOE', so I'm guessing that is the one used by game as default for that team. I'm not 100% about that tho, but you could try...
Yea, that was what I was talking about. In edit player, every team has a default shoe; so you could try to edit that value in teamgear.dbf and see if it changes in the game...