Well, you could hard-script it (Man, that sounds so weird.
) and set up a bunch of variables using the new system that pertain to each possible weapon.
I doubt you're going to over-ride the fact that pressing a number will autoswap your weapon to the weapon that FPSC thinks you're wanting to grab, that is... unless you Mod the source.
I think, given the amount of introspective philosophy behind the setup (Yes, I just pulled that outta my ***) You may have to sit down and think about how your desire system is going to work, knowing that the number keys are already bound to the inventory created by FPSC.
Come to think of it... I don't think there are any scripting commands to change weapons in the official updates.
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Yup, you're SOL. Sorry, Deathead!
The one and only,