Can missiles pass through a Resilient Sphere created by a Shadow Evocation?

Question

I think Shadow Evocation is usually used as an offensive spell and the rules cover that quite well.

However, my NPC is about to use it to protect himself from a whirlwind of flying glass that an Air Element is about to create (by placing himself in a Resilient Sphere). He'll weather the storm and dismiss it when it suits him - or so I thought.

Disbelieved Shadow Evocations are only 1/5 effective. But who has to disbelieve the illusion, the Air Elemental or the mage that summoned the Air Elemental?

Or do the glass shards simply penetrate (with 4/5 effect) the sphere because they're objects:

Objects automatically succeed on their Will saves against this spell.

N.B. Shadow magics are "partially real" according to the magic rules:

Shadow: A shadow spell creates something that is partially real from extradimensional energy. Such illusions can have real effects. Damage dealt by a shadow illusion is real.

Answer 1

No one needs to disbelieve, missile attacks will pass right through

From the srd

Creatures encountering an illusion usually do not receive saving throws to recognize it as illusory until they study it carefully or interact with it in some fashion.

And then from the spell there are two lines I think are worth quoting.

Nondamaging effects have normal effects except against those who disbelieve them. Against disbelievers, they have no effect.

So if whoever needs to believe disbelieves the missiles will have their full effect. The 1/5th stuff only applies to attacks.

Objects automatically succeed on their Will saves against this spell.

The missiles hitting the resilent sphere is pretty clealy interacting with it. The missiles are objects so they automatically make their saves. Being a wall is a nondamaging effect so your shadow resilient sphere has no effect.

Afterward the Air Elemental gets to make a save to disbelieve

Throwing glass shards at you (and seeing them go through your resilient sphere) is enough that the Air Elemental has interacted with your illusion and now gets a saving throw. If the Air Elemental makes this save then the shadow resilient sphere will have no effect against anything else the Air Elemental does after that.