Using player weapons while in a vehicle

Done a fair bit of searching.
Can’t find any relevant code, and either i’ve missed it or no one has asked.

How to allow players to use their weapons while in a vehicle?
ex. Jeep, airboat seat

And i’m not talking about the attached turrets.

Any ideas?

In the next update/dev branch:

[editline]17th May 2014[/editline]

Note that in 99% cases ( with exception for chairs/seats ), you will shoot the vehicle itself.