Before observing with INTEGRAL, be sure to issue the following commands (along with the usual ZEROSET's, CAL LAST's and so on) when setting up the TCS:
USER GHRIL ROT
USER INSTRUMENT OWN
USER AGSELECT GHRIL
Note that having done a calibrate on the rotator centre, a nominal aperture (aperture zero) can be defined in order to place the telescope reference position at the center of the acquisition field. GSS will take account of such an aperture if you enter APERTURE x y at the GSS prompt before searching for guide stars.