AFAIK, Cryptopia does not allow mining (from pools) directly to their wallet.
Check it out yourself when you go to deposit Zero (or any other currency), click get address and then read the small red font.
they say not to do it.. personally I am not sure why but some people have recommended this against that statement and I haven't noticed any complaints about such a practice. still seems bit wonky though. there should be a command line wallet out soon..
you can set the address from cryptopia just fine in the mining pool, what they don't want is lot of small transactions as it dusts their wallet, so on a mpos like pool where you only withdraw "bigger" amounts it should be ok.. they don't want to have thousands of users dusting their wallets with super-small inputs obviously