The artillery spawned by the AI just drives towards the enemy till they get blown up.
Is this intended? Come to think of it i don't think i've ever seen the AI use artillery on me while playing ALIVE.
I have not totally sure, but I'm gonna go out on a limb here and say even without ALiVE, just placing artillery around the map in the vanilla editor, enemy artillery won't fire unless scripted or commanded to. Fairly certain also that ALiVE Combat Support artillery, if that's what you're using and not just manually placing the artillery, is a player only feature and not autonomous.
Easy way to test really. Place some artillery down in the editor (no ALiVE). Place some enemies and see if the AI is smart enough to use them on their own. I doubt it.
If they do, but don't fire when using ALiVE, could you report back in more detail with how your mission is set up?
I'm big on Artillery, and I've had good success with it. However, you'll find that AI Artillery will only operate once they've been spawned in by the player being X distance away. What I've found to be successful is by implementing it in a couple ways. First, you'll definitely want VCOM AI if you want the AI to use Artillery effectively. Once you've got VCOM, any AI artillery spawned in will fire at enemies that are in contact or spotted by other AI units. I'll use stationary batteries like the M119s in the Artillery group as well as Self Propelled Artillery.
Also, I'll use ORBAT to create Support Infantry groups that are set to spawn with static mortars. These units will be in various places on the map, typically just behind the lines, and will also drop shells on enemies spotted by their friendly AI once they've been spawned.
This is really the only way I've found to get Artillery working like I want.