Somebody have working setting for 280X? I've got only rejects

Do you use the correct kernel (x11mod)?
I have got the same problem and it was the solucion.
setx GPU_MAX_ALLOC_PERCENT 100
setx GPU_USE_SYNC_OBJECTS 1
sgminer.exe --kernel darkcoin -o stratum+tcp://stratum-eu.suchpool.pw:3345 -u xxx -p xxx --lookup-gap 2 --thread-concurrency 8192 -g 2 -I 13 -w 256 --auto-fan --gpu-fan 55-80 --temp-cutoff 70 --temp-overheat 75 --temp-target 72 --gpu-memclock 1450 --gpu-engine 1160 --gpu-powertune -20 --no-submit-stale