If you can't find or locate an O-style symmetry operator file for your spacegroup: Phil Evans has deposited a Fortran program in the OMAC directory which will read the CCP4 SYMOP library and generate O symmetry operator datablock files for all spacegroups (encountered in protein crystallography). The source is in file://rose.bmc.uu.se:pub/gerard/omac/gen_o_symm.f, an SGI executable is in the same directory. Before running the program you may have to do:
setenv SYMOP /nfs/public/packages/ccp4/lib/data/symop.lib