Modifying the Weapon Selection at the top of the screen?

This is just a simple question, where can I find the files to modify the Weapon Selection when selecting weapons with the Scroll Wheel?
Or is there a free example of one, i could use and test?

[editline]27th May 2015[/editline]

I understand there’s something called GM:CHudWeaponSelection or CHudWeaponSelection.
But where do I find it.

You can’t edit it, you can only hide it and create a new one from scratch.

How would I go about creating a new one from scratch, any examples?