Air New Zealand Air Points - Surprise Birthday Cake on NZ Flight?

Hi All - As it's now been two years since my last surprise birthday trip for my mom, it's time again for another. We're departing in a few days LAX-RAR, and then a return AKL-LAX (she has no idea that we're traveling anywhere other than LA, so it should come as a nice surprise). I wonder if there is any way to arrange in advance with NZ to have a small birthday cake (or something birthday-ish) loaded on either flight?

I'm happy to pay for the privilege, but I'd prefer not to purchase one on my own for hand-carry onto the aircraft as it would likely be discovered by my mother either at security or perhaps as we try to make our way into the lounge. If this isn't possible, does anyone have experience with bringing your own? I suppose cupcakes are probably the best?

Anyone else on our flights? If so, stop by and say "hi" - We'll be happy to share birthday cake with you (if we have it)... :p

NZ019 LAX-RAR 13SEP
NZ002 AKL-LAX 20SEP

For the AKL-LAX leg you could try getting in touch with AirNZ Customer Service, as that flight will have an IAC (International Airline Concierge) who helps with these types of requests. They may not even charge you for the cake as the IAC will have a company credit card for these sorts of things (some IACs purchase a small cake for elite customers if they are travelling in their birthday month etc). Worth a shot, thats part of their job!

Last time I tried similar was for a honeymoon flight (not mine). NZ refused point blank to allow anything special even though I offered to pay for it (even deliver it to the airport if required) plus a generous fee for their trouble.

Admittedly this pre-dated concierges (but there are none on LAX-RAR).