First, in order to use packet injection, you have to get a program which is able to build packets and (re)sent them.
Second, you have to capture packets coming from the ps3 source.
Third, use the captured packets to modify to needs and/or resent them to server.
Ps3proxy comes in handy, cause it can work with another program who can block certain
traffic from specific applications.
That was the whole purpose of ps3proxy...