Worthless 3d rotation tool :/

Question

Okay sorry bout the vague thread title but this is pissing me off.  I imported a bitmap, converted it to a vector object and created a motion tween.  In the first frame I used 3d rotation on the x-axis to tilt the image away from me, so it looks like this:
Now what I am trying to do in the motion tween is spin this "flattened" image all the way around 360 degrees like a turntable.  So I divide my timeline into four sections; my animation is 120 frames long so I start by putting a keyframe at 30.
In frame 30 I change the x-axis back to normal so it looks like the original 2d bitmap again, rotate it 90 degrees with free transform (or using the z-axis in 3d rotation, either works), then use the x-axis to flatten the perspective again.  The tween works great so far; between frames 0-30 it spins 90 degrees like a turntable when I scrub the playhead.  I do the same thing again for frame 60, and again it works the way I intend, now having been spun half way around.
The trouble is once I try to spin it any further than half way, even if I orient it correctly, from that point on Flash decides to make the tween move in a completely different direction than before, taking the long way around and flipping the entire thing upside down and over and back in some ackward path that completely deviates from the motion I had going during the first half.  I have tried and tried and tried to make it do what I am trying to get it to do but Flash keeps on second guessing me and tweening it a different direction; even if I rotate it just a tiny bit further Flash will flip it all the way over to get there, instead of taking the more obvious path and spinning it just a little more.  This is pissing me off because it just will not do what I am telling it to.  And if I try to enter rotation values into the transform panel, Flash always changes those values to some arbitrary numbers as soon as I hit enter or click somewhere else, if I change the Z it will change the X to some weird number, so I go to change the X back and then it changes the Z, so that panel is pretty much worthless for entering rotation values I've found.
If any method exists at all to make this do what I am trying to do, I would like to know what it is.  Any help is appreciated, thanks.

Answer 1

Timeline-based tweening can sometimes be difficult to tame.  Have you tried using actionscript instead of using a timeline tween?  I haven't dealt with 3d aspects of Flash, but you should be able to gradually incremement the rotationX property of the object.  If you gave the object the instance name "mc", then the folllowing should work...
addEventListener(Event.ENTER_FRAME, spinMC);
function spinMC(evt:Event){
    mc.rotationX += 1; // increase number for faster spin