Ok, i have discovered that i have encountered this problem earlier
here.
I want to create resurrecting enemy unit, but exploding corpse can not spawn new unit.
Only way i found - is to add special item to the unit inventory, which will fall and detonate. But it is ugly and causes many odd situations ingame.
Best decision (for modders) will be support of spawning units not only from grenades, but from corpses too.
I see no script possibilities to spawn new unit from corpse, so maybe it will stay as it is now.