I agree with D. The important part is to understand your role in the APQP process (PPAP is really only submission of the warrant and all the APQP stuff such as D mentioned and the fmeas, etc.).
You might want to take a read through the section on documentation mapping and relationships starting at http://Elsmar.com/Imp/sld190.htm
It's as applicable to ISO as it is QS.
Every corporation / company structures things such as documentation differently. Take an extreme example - Motorola. Everything starts at the IL headquarters - which has certain policies and procedures applicable world wide. Then there are sectors while must know what ones apply to them and what they need there to 'fill any gaps' AND what they have written which is applicable to those divisions under them. Then there are.... etc. right down to the individual facilities. When I worked with the semi-conductor sector, the documentation aspect was extremely difficult because of gaps in the structure (which we fixed). Make sure you know what exists and are sure the backbone is sound before you integrate. And get buy-in from other facilities - make sure everyone agrees to the structure and who is responsible for what.