I need to use a “dihedral shift function” as torsion potential in Mesocite. The reason is that the "dihedral shift" was used in the original papers on "MARTINI forcefield”. 

But It seems that it is not possible to use the “dihedral shift” in Mesocite forcefield manager and just the "dihedral" function can be used.

If that is right, is there a way to define the “dihedral shift function” in the forcefield manager of Mesocite ?