Yahoo push mail actually work iPhone

I have owned iOS devices since they first came out, and I have never managed to get Yahoo! Mail to actually work. I have a @yahoo.com address and also a @xtra.co.nz address which is Yahoo-delivered (xtra is a ISP in NZ which is owned by Yahoo!) and I have never once managed to get push notifications to work for either accounts on either my iPhone or my iPad. I have always just accepted it as something that is advertised but doesnt actually work, but really that cant be. Has anybody here managed to get Yahoo! Mail to push, or is it just a crock? Am I doing something wrong?
Thanks
Steve
Message was edited by: stevelawrencechch
iMac (early 2009) 20" / 2.66Mhz Core2Duo / Mac OS X (10.6.7) iPhone 4 16GB (Black), iPad 3G 64GB