Seems that I still can't sleep well...

Sorry Ashar, I "hijack" your thread for my descend issue with POSKY 744. ;)
I flew B744 POSKY EVA Air (it is B744 v3, isn't it?). ATC cleared me to descend from FL310 to FL180 about 110 nm from destination. Weather clear. No wind.
As usual -and looks only happen with me- the bird descends like a falling broken-rope elevator box, although I have set the throttle to idle during descend, but still the IAS stays at 310-320 knots!!!
I passed 10,000 feet, and was forced to use spoiler to gain 250 knots - with the consequences of nose pitch up to 5 degree.
Autopilot is engaged till 1.5 nm before destination.
I just feel this is not right.
Can someone advice me what is the best and proper practice?
Thanx.