1. Press A (CLR) to go to VFO mode
2. Press and hold down F and then press 8 (set)
3. Press * or # until you see the letters OW in the right side of the screen
4. Use the VFO knob to change the offset
5. Press A (CLR) to exit the set mode.
For some reason ICOM doesn't have the IC-4SAT manual online, but they do have the IC-3SAT manual, which should be the same, except for being for 220 instead of 440.