It's not like Alice's photon somehow transmits an "I've been observed as H polarized" message to Bob's photon. These "both alive and dead" and "mixture of H and V" statements are euphemisms for "Unknown".
That is, unless I'm missing something fundamental.
Apparently, because that is in a way what is going on:
The both 'alive and dead' IS NOT an euphemism for unkown... A single system can be in a superposition of two states. In this case we are talking about a single system consisting of two photons.
Measuring the state in a certain base on one side WILL collapse the wavefuntion of the entangled pare.
See for example also the 'wheelers delayed choise experiment':
http://en.wikipedia.org/wiki/Wheeler's_delayed_choice_experiment
However, even if the system is 'pushed' into one of the eigenstates of the measurement machine, it can still not be used to transmit information faster then light.