It doesn't seem like it's possible to customize your kit, except for when you are playing or in the main menu (i.e. not between matches). Or am I missing something?
It's currently impossible to change any settings outside of a match. This includes kits.
However it's a highly requested feature to let us customize kits on Battlelog, and a DICE employee has stated that they're going to look into it, however that doesn't mean it's going to happen.
You have a period of time between matches when you can customize your kit and that's when the new map has been selected and the countdown timer hasn't reached zero. I'm talking about the time where you deploy but you cannot move around (only jump, switch weapons or drop boxes).
If you don't deploy, you can hit
One thing I've noticed about this is that you can only customize kits that are relevant to the current map. So for instance, you won't be able to customize the
If I remember correctly, you can also access this menu when you are dead and haven't respawned yet.