but are you sure to have selected the Correlation device on Alarm setup? The signature works on Correlation engine.
We currently have that rule working in 9.3.0 Build 20130919112150. I would suggest that you remove the "Destination IP" as one of the Group By options in the correlation rule. I've had issues before when I've selected multiple "Group By" options. Once that is removed re-apply the policy to the Correlator then watch to see if you start seeing alerts in from the Correlator.
Another trick that I was told from the support staff was that for simple filter correlation rules to not bother with the "And" or "Or" options. My rule currently looks like this