Use XPAND: Have you ever tried to completely specify your symmetry to X-PLOR when using strict NCS (chapter 20.2 of the X-PLOR (3.0) manual) ?? If so, you'll probably be happy to learn that this can now be done automagically with XPAND (pub/gerard/xutil). You supply your NCS and SGS operators in O format, your cell constants and a safety margin, and XPAND generates a complete NCS-strict include file for X-PLOR. See the on-line documentation for details and an example.
NOTE: the reason you need to go through all this trouble is that X-PLOR switches off non-bonded interactions that arise due to crystallographic symmetry when strict NCS is used in the refinement.
NOTE: I *think*, but am *not sure*, that the algorithm works correctly. Send bug reports directly to "firstname.lastname@example.org".
NOTE: be prepared to re-dimension X-PLOR ! The number of NCS operators required to completely specify the NCS PLUS SGS symmetry increases exponentially with the number of crystallographic NCS operators. Typically, for two-fold NCS you need an additional ~8 operators; in the case of four-fold NCS you may already need more than twenty (poor virus people . The parameter you need to increase in X-PLOR is MNCSYM (the default value is 20, I think).