Box2d Filter and doc

Hi

Filter collision is probably one of the hardest part of Box2d.
In documentation the ShouldCollide example has syntax bug.
Should be :

Local Collide:Int = (filter1.GetMaskBits() & filter2.GetCategoryBits()) <> 0 And ..
(filter1.GetCategoryBits() & filter2.GetMaskBits()) <> 0
return collide

Isn't there any way to register a b2ContactFilter ?
Overrided ShouldCollide() is never called.

About Collision Bits now
Do you think it's better to do like this :

Const PLAYERONLY_COLLISION_BYTE:Short = $0001:Short
Const GOLFBALL_COLLISION_BYTE:Short = $0002:Short
Const GOLFBALL_SENSOR_COLLISION_BYTE:Short = $0004:Short
Const OBJECT_COLLISION_BYTE:Short = $0008:Short
Const PLAYER_COLLISION_BYTE:Short = $0016:Short
Const HOLE_COLLISION_BYTE:Short = $00032:Short
Const GROUND_COLLISION_BYTE:Short = $0064:Short

Or values should be rather like that :

Const PLAYERONLY_COLLISION_BYTE:Short = $0001:Short
Const GOLFBALL_COLLISION_BYTE:Short = $0002:Short
Const GOLFBALL_SENSOR_COLLISION_BYTE:Short = $0004:Short
Const OBJECT_COLLISION_BYTE:Short = $0008:Short
Const PLAYER_COLLISION_BYTE:Short = $0010:Short '$0010:Short = 16
Const HOLE_COLLISION_BYTE:Short = $00020:Short '$0020:Short = 32
Const GROUND_COLLISION_BYTE:Short = $0040:Short '$0040:Short = 64

The thing is I found it very hard to setup correctly my player collision mask.
Player should collide with everything at certain moment (see FULL_MASK_BITS)
Sometimes Golfball must pass through (see PLAYER_MASK_BITS) when refiltering.
And a certain kind of object (PLAYERONLY) shall never collide with anything except player.

Const FULL_MASK_BITS:Short = $FFFF:Short
Const PLAYER_MASK_BITS:Short = $FFFF:Short ~ GOLFBALL_COLLISION_BYTE
Const PLAYERONLY_MASK_BITS:Short = $FFFF:Short ~ OBJECT_COLLISION_BYTE ~ GOLFBALL_COLLISION_BYTE ~ GOLFBALL_SENSOR_COLLISION_BYTE ~ HOLE_COLLISION_BYTE ~ GROUND_COLLISION_BYTE

I know it sound confusing but I'm wondering if it's the good way to setup collision filters since everything work like that.

Thanks if you can help