Think through the dynamics of what you want to achieve.
VS is useful for a controlled rate of descent, it is seldom, if ever the correct way to achieve a high RoD. I was taught (on 737) that VS is not a suitable mode with power in the lower quarter of the range, or close to the top as reaching idle or max thrust will begin to affect the speed, so in those thrust regimes use Level Change or whatever equivalent mode you are equipped with. Failure to observe this basic precaution will eventually lead to a speed exceedence at one end of the range or the other. If you need more RoD than can be achieved with idle thrust either increase IAS or maintain what you have and use speedbrake, or both, which is used depends again on the situation, ie is speed able to be varied?
Using speedbrake to increase RoD when higher speed is not a problem is a clumsy technique, but of course close to (or intercepting) the approach increasing speed is a good way to get yourself into a pickle.
I regard using speedbrake to slow the aircraft as clumsy too unless the reduction is urgent which is rare. It isn't intended to be used like the brakes on a car. We'd be better off referring to them by their proper name, "Spoilers" which is less likely to form slowing down associations in the minds of junior (and some senior) pilots.
As said elsewhere the gear is a useful and valid option close in too.
Finally, if you can't comply, tell ATC. They will have to give you a workable option, be it more miles, a turn, changing the clearance etc. That is up to them, and you can suggest what you can do as said above. It's your show, not theirs!
Last edited by Agaricus bisporus; 9th Jun 2012 at 08:55.