Station not launching defenders

[Zieman]

test 1.74 and WinXP 32 bit

I've made a station and designated denfense ship for it.
The problem is that when I try to test 'em by spawning a few thargoids @ launch, the station doesn't launch any defenders , even when the thargoids fire at the station.

The setup includes
max_police = 0;
in shipdata.plist

If I set max_police to 1, the station launches 1 police, but no other ships.

After the thargoids are gone, a bunch of defense ships come to look at the carnage.

If I shoot the station alone, those defenders do appear. But when thargoids are around, no defenders in sight, no matter who shoots.

[Switeck]

Pirate Coves OXP seem to launch "regular" pirate/trader type ships as defenders.
You looked at its details for ideas?