A B747-200 encountered a stick shaker while configuring on a visual approach.

Narrative

We were arriving from Europe. We were descended very early; and were below 10;000 MSL by about 70 miles out. Everyone was very concerned about VFR traffic; of which there was a lot on TCAS. The ILS was out of service and we were assigned a visual. We were given a vector for about a two mile final at 3000 FT MSL. When we declined; we were given a down wind and about a five mile base. During the tight base; we were assigned 2000 MSL. During the descent; I commanded Flaps 20; gear down; landing checklist and Flaps 15. ATC had turned us too far; and I was turning back out to intercept the centerline. The Captain was also trying to program The FMS to provide back-up glideslope data. Possibly because of this; he did not reduce the command airspeed bug for the new flap setting. Against our SOP; I reached up to change it myself. About this time; the autopilot captured the altitude; and when I looked down; the aircraft was about 20 KIAS below bug. I applied go around thrust; and shortly there after; the shaker activated briefly. The Captain pushed the yoke substantially forward; and then I disconnected the autopilot and continued to push down. The landing finished with no further incident. Contributing was ATC treating a B747 like a C-17. Configuring in a descending turn onto a short final surely contributed. In turn; being told to descend so early led to fuel concerns; which discouraged configuring early. Fatigue surely was a significant factor. We had crossed the Atlantic overnight; arriving just 24 hours before starting the flight. I slept badly; going to bed three times.