Psykic Powers and Fortifcations

I thought I would bring this little gem here for a discussion. I was playing against an Eldar player with multiple Farseers that had generated Invisibility among other nasty powers.  Now to add insult to injury he brought the Aquila Stronghold to counter my Reverent Titan, which is fine and all until he decided he was going to cast Invisibility on his fortification.  We both scoured the BRB and came to the same conclusion that it was a legitimate according to the rules.  I'll quote the rules that brought us to this conclusion, I just wanna hear what you guys think cause honestly you guys are great at figuring out these conundrums.

- Friendly and Enemy Models:
All models on the same side are friendly models.  Models controlled by the opposing side are enemy models.... etc.

- A claimed building is a unit in the controlling player's army and will remain so, even if it later becomes unoccupied, until the building is either destroyed or claimed by an enemy.

(P.S. I got tabled.  My Titan went down quick to the Aquila as did the rest of my army, cause lets face it Dark Eldar realistically can't answer AV15 with Void shields and Invisibility on it lol)

Rulebook p. 110
When determining if a building can be targeted by a shooting attack or psychic power, charged and fought in close combat, or affected by a special rule, treat the building as a vehicle unless specifically stated otherwise.

Quote :

(P.S. I got tabled.  My Titan went down quick to the Aquila as did the rest of my army, cause lets face it Dark Eldar realistically can't answer AV15 with Void shields and Invisibility on it lol)

AV 15 = Easy
Void Shield = Easy
Invis = Not so much

Edit: On a side not.... The Aquilla being invisible probably meant his psycker was not invisible, so why not just kill him?

No doubt they were inside.

The Red King wrote:

No doubt they were inside.

In that case the psy shouldn't be limited to cast witchfires only?

Witchfire only if the psyker was inside. Otherwise just kill the farseer sounds about right

What about them being on battlements ?

That would work. But you would still be able to shoot them then.