Certified document and page adding actions

Hello,
I have a document created with acrobat Professional 8, it contains 3 signature fields.
The first signature certifies the document allowing form fill changes and Page adding so the other fields can be signed by other parties. I.e. : the first signer certifies the document and the other signers agrees to the terms ...

I have 2 questions:
- is there a way to specify that only form fill in is allowed and Not page adding (when creating the document or when applying certifying signature) ? Anyway how can anybody add a page on a certified document ?
- Acrobat 7 always shows a yellow mark on the second signature after the third signature is inserted, that is confusing and we would like the document to be compatible ONLY with at least acrobat 8. Is there a way to specify that a document should not open in some version of acrobat.

with thanks in advance

Laurent Merchez