Hmm, weird. I also have a saitek stick, but a little more traditional one (cyborg evo, to be matter-of-fact).
But when I swapped the controls from my old Logitech Crapstreme 3D Pro, I noticed that Saitek uses different names on their sticks' axis' - at least this is how they are named on Cyborg evo:
X and Y axis are traditionally named, but twist handle rudder is named rX (as rotate X), and throttle is named z-axis.
Have you lately switched to Saitek from some different mark, or has this controller been on use from the first time you learned about The Babylon Project?
May I presume that you have checked what axis names are on places for Bank and Absolute throttle on your controls setup in TBP? I'm quite sure you have already tried the bind-action, but just to make sure I must ask this, too.
If this doesn't help, you could try the Saitek Smart Technology tool and create a profile that recognizes throttle as something else as the default.
Weird, still, because my TBP controller setup recognized Cyborg Evo with no problem - i just had to choose "bank" and bind it to twist handle axis by twisting the stick, and bind the throttle to absolute throttle axis by same method.
It might be that S 45 is somehow a bit too complex or something... isn't that the one with two analog roll buttons on it in addition to normal axis'?
I don't claim to know too much of gaming controllers, I just received some major help today here - and as I also have a Saitek controller, I figured to ask if you had noticed the same things that I have, when comparing Saitek Products to, say, Logitech ones - that is, if the Cyborg Evo and S45 use even remotely similar axis naming system.
Good luck with finding solution, if this doesn't help.
EDIT: Oh, btw: It could be useful to know some more facts of the system you're running TBP. Actually it'll most likely be needed if some more suggestions are to be made...