My solutionn is using RF transmitter/receiver with Arduino.
Arduino communicate with Smartthings via Smartshield.
With this method I can control 4 ceiling fans & some RF switches from Etekcity (which use RF 433 remote).
Check this thread
https://community.smartthings.com/t/st-anything-433mhz-rf-devices-arduino-thingshield/19084