How can the extended range mode in a PT-D46 be enabled?

If the D46 pan tilt unit (PTU) is standard, then you should be able to get the extended range of motion by disabling the limits with the LD command, then DS to save. You may need to reset the axes as well, using the RE command. Then the normal limits will be ignored, and you can issue position commands outside of the standard range. Please note that velocity mode commands are not supported outside the standard range. To revert back to the standard limits, FLIR suggests using the following sequence:
Sending the axes back to zero first will ensure that the axes are back inside normal limits before re-enabling them.