XModMorphismAutoPerm( X, perm )
Given the isomorphism between the automorphism group of X and its
permutation representation PermAut(X), an element of the latter
determines an automorphism of X.
gap> XModMorphismAutoPerm( XSC, (1,2)(3,4)(6,7) );
Morphism of crossed modules <[c3->s3] >-> [c3->s3]>
GAP 3.4.4