[LUA] How to add a playermodel into the list

[Nikout]

What do I need to add to put a custom player model into game's list to select and play as? I remember that GM 12 had an other type of player model menu base but in this time it's different.
Do I need to add only that or something more? (I'm a dumb in LUA, so please, do not throw a shit to me).

AddValidModel( "mebf3",		"models/nikout/masseffect3/coop/player/soldier_bf3.mdl" )

[neesu]

For me,

list.Set( "PlayerOptionsModel", "Gaige", "models/Borderlands2/Characters/Gaige.mdl" )
player_manager.AddValidModel( "Gaige", "models/Borderlands2/Characters/Gaige.mdl" )

worked.