So at the pole you had your service drop and a 100amp panel which was connected to a grounding electrode?
From there you went to another panel within the dwelling?
Prior to the 2008 NEC you were permitted to use the grounded conductor for grounding if you went to a separate structure. The one sticking point was that the two structures could not have metallic paths between them (water pipe, phone line, etc.). The second structure was then treated like a normal service with a bond between the grounded and grounding conductors and connection to a grounding electrode(s).