I believe the issue might be that the 3806 can output different sources to Main, Zone2 and Zone 3.
From looking at the manual, for "Power Amp Assign" setting select "Zone 2" and use the Surround Back Speaker Outs for the patio speakers.
For the first time you will need to select the Zone 2 source. For this have your PS3 up and running. Then from the remote, have it control the Zone 2 amp and select the input to be the PS3.
If everything works like the manual says, you should be in business. Also, since the amp defaults to previously played input, you should be able to control the patio speakers by simply turning on and off the Zone 2 amp and will not need to select the PS3 input every time.