Here's an interesting tidbit of information from the CX website that everyone seems to have missed (emphasis mine):
As Premium Economy Class is a brand-new Cathay Pacific product, other award redemptions will be made available in phases. One-way or round-trip awards on Premium Economy Class will be available from June 2012, with upgrade awards from Economy Class to Premium Economy Class to be introduced in the 4th Quarter of 2012. By this time, a one-class upgrade policy will apply as usual, meaning Economy Class ticket holders will be able to redeem an upgrade to Premium Economy Class, and Premium Economy Class ticket holders an upgrade to Business Class. Upgrades from Economy to Business Class will still be available on flights without Premium Economy Class cabins. For award details, please refer to Awards Charts.