Warhawk Omega Dawn Pack NOT Reigon Free!

I just found out the hard way. I have the US version of Warhawk on a Japanese PS3, and just purchased the “Booster Pack” to Warhawk. It does not work. A waste of $8. I’m pissed. I should not have to find the FAQ page to read if it is region free or not, there should be a region code check before allowing you to download content that wont work. I was looking foward to playing the new maps with the drop ship, now I have $8 less and a addon pack that wont work. Other than somehow getting my hands on a US credit card is there any other way to get this working ?