Control existing Honeywell RF sensors with Smartthings

Just got Smartthings and like the many before me trying to see if i can get my existing Honeywell sensors to talk to it. My current setup has a Honeywell Door/Motion sensors and a Siren and a Alarm panel (FA168CP). Learnt last night that the sensors talk to the panel through RF.

What is the way to get Sensors to talk to Smartthings either through the panel or directly. I combed through a lot of threads last night but slept even more confused.

is this worth the attempt or am i better off getting new sensors.