But Cloud of Knives doesnotautokill minions.
Edit: Let's make this a bit clearer.
The "Effect" is part of the attack. The attack is a missed attack. Hence, no damage.
Corrected that for you.
The secondary damage of Cloud of Daggers is irrelevant to the miss.
It is damage. It kills minions. It is not due to a Miss, it is a damaging effect regardless of hit or miss.
Customer Service has concurred.