What skill does a forger use to forge a document? I don't seem to find something usefull on the character card….

I would use coordination, skullduggery or Tradecraft. Allow the player to specialize accordingly.

Here are the difficulties I'd use:

Forge a letter identically: skullduggery or coordination (or education acquired) 2d to 4d

Forge a letter that changes what a person has written: add education for certain: +1 or +2 difficulty

Forge a badge of wood or metal: Skullduggery or coordination or tradecraft (specialization forgery in whichever one the player has chosen): 1d to 4d

Create an engravers punch for a coin-press: tradecraft, skullduggery or coordination (of course all the value is in the metal) 2d to 4d

Create a wood-cut for a copy of a signet ring for wax impressions: skullduggery 1d to 3d

Create a duplicate of a painting - 3d to 5d (masterpiece)

Now, NIETHER education nor tradecraft are career skills, but would be invaluable to any character gaining them. Education would be exceptionally important when attempting to change any written materials, otherwise you're dealing with mis-spelled words and the like while doing writing activities.

jh

~Typical Trappings: A forger often carries with him

Yeah, Emirikol has some great stuff here. I don't disagree with anything he suggests. It is what I would suggest.

To forge a document I would go for Skulduggery (Int) check. Remember though that a character needs Education to be able to read or write