Warfare & Tactics

Hello, capsuleers, im quite a noob in Eve, so i am really need your help now.:)

My alliance declared war on corp which owned a POCO, but somehow they manage to transfer an ownership to another corp.

I learned that ownership can't be transfered if corp is in war or in war-pended status. But they did it, and when we came to that office 24 h later we didn't manage to attack it without being concorded:( We paid to start war, to destroy the POCO, and now we have 1 man corp against us without the war prize for us:(

Would you tell me, please, how did they do it? Is it a trick? or maybe its a violation of something? Or maybe everything is legal, and they paid to CONCORD, or have amazing standings with them, idk what else.

P.S.: Customs office gantry is a customs office, right?