You need to edit your bindings file manually so that
only the axes you want to curve are controlled by vJoy. All your buttons would remain mapped to the x52.
So your
Custom.binds file might end up looking something like this:
Code:
...
<RollAxisRaw>
<Binding Device="vJoy" Key="Joy_XAxis" />
<Inverted Value="0" />
<Deadzone Value="0.00000000" />
</RollAxisRaw>
...
<ToggleFlightAssist>
<Primary Device="Keyboard" Key="Key_Z" />
<Secondary Device="SaitekX52" Key="Joy_32" />
<ToggleOn Value="0" />
</ToggleFlightAssist>
The way to do that would be to select the x52 profile, save it; thus creating a custom file, then manually edit it to change the appropriate lines.
Binding axes in the game may fail when you use vJoy because when you press a button or move an axis the game will receive inputs from both vJoy and the raw device, and you don't know which one it will decide you meant to bind.