Abutment modelling in RUAUMOKO 3D for curved superstructure

https://i.servimg.com/u/f47/17/37/92/37/curve_10.jpg
https://i.servimg.com/u/f47/17/37/92/37/spring10.jpg


Dear All,
I have a problem while modeling abutment in Ruaumoko 3D, as global axes in plan as shown in figure (first link above) are Xs and Zs, while the abutment local axes for the curved bridge is Xc and Zc (makes an angle θ with global X-axis (Xg).
Now the problem is if the displacement in the local Xc direction is allowed while restraining in local Zc direction, what I should do.
I was looking for the option to change the local axes of node at abutment i.e from global Xg and Zg to local Xc and Zc, however I didn’t find anything in ruaumoko 3D manual.
Second option is to provide zero length spring but it is also not possible as zero length spring is always in global axis direction.
The third option that I am trying to do is to provide line spring. For local direction (Xc), Kxc is the translation stiffness of spring while for transverse direction (Zc), Kzc is the translation stiffness. But for line spring there is other complications, like defining these two nodes (1, 2) extra and also as this is line spring. What about shear etc on spring…? Is this correct modeling? (for figure follow link 2 above).
Can I define just one node and one spring and assign the different spring properties (translation and rotational stiffnesses?
Thanks for your attention and look forward for your's reply,
Easa