I'd be interested in knowing your source for the UN having the authority to determine the boundaries of a sovereign State, especially in contravention of a treaty.
I mean, seriously, follow this to its logical conclusion. The UN can unilaterally just change the boundary of a State? USA needs to be smaller and Mexico needs to be bigger, let's just create a new boundary?
Colonizing occupied territory is against the international law. Remember we didn't let Saddam keep Kuwait.