I found that I didn't have 7 digit postcodes immediately after the update.
Then as if by magic, 2 weeks later I tried a new address and it let me enter 7 digits.
No special menus needed, you just enter the postcode as normal and it simply allows you continue and add digits 6 & 7 whereas before it would stop at digit 5.
So now I have 7 digit postcode!! mine's a Mar 09 build, but had an update before they changed the HPFP in late 2010.
Last edited by doughboy; 12-12-2012 at 08:55 AM.