Need help wiring a 3-way Honeywell digital timer switch
You should follow the instructions included with the device.


  
  
  Connect wire "C" of the RPLS530A/RPLS531A to the "common" wire,
  identified when removing the old switch. Connect the other two
  RPLS530A/RPLS531A wires to the two remaining wires.
  
  At the other 3-way switch, connect the jumper wire between the "common"
  screw and the screw where wire "1" of the RPLS530A/RPLS531A
  is connected.


So your diagram will look like this...