Is it possible to mod the game so full attacks will use both a melee weapon and a ranged weapon on turn-based mode?

[SorenArkwright]

Hey, I'm never modded anything in my life so I figured it would be wiser to ask before I spend hours trying to make something.
I wanted to make a character that uses both a rapier and a pistol at the same time, but after some googling and a few minutes of testing I'm pretty sure it's not possible to do it in the base game, as the character will always use either melee or ranged weapon but not both, even with full attack skills that allows for both ranged and melee, samething happens with the basic attacks on turn-based mode where you always supposed to use both weapons if you are dual-wielding.
I looked around for a mod, but didn't find anything. The game is almost 6 years old, so I asume it's well understood by now.
Is this possible to accomplish without breaking the game?

I'd be grateful for any information.