Hi Ralph,
If the iFly 720 is running the latest software, you should be able to connect the two via Wi-Fi and tap Menu -> About -> Connected Devices and select the Stratus (beta) from the Wi-Fi Ports list. Below are a couple of things to check, just to be sure it is connected.
In the Set Up page, make sure you disconnect from any "PRE" networks. Then let the list refresh and connect to the Stratus...tap the IP setting and confirm you are getting numbers in the IP address and the Subnet Mask boxes. If not, you might make sure it is set to DCHP at the top of the page and start over. Some of the older SkyRadar's used Static and we just want to make sure this is not carried over from a prior config or selected by accident.
Once you are getting the IP address and Subnet populated, then you should be able to enter into the Nav and check whether you see Weather Pre-Flight or ADS-B in the Modes. Give it about 30 seconds to a minute to make the handshake, just to be sure.
With the newer software, I don't think it is necessary to change the settings.xml file any longer. Once the two units are connected and talking, you should see the Weather change from Pre-Flight to ADS-B Live, No Data or Idle. Then you likely just need some Altitude. I hope this helps.