Yes, I understand that, that is why I put a link on post #2
and here's another one:
http://www.census.gov.ph/civilregist...ublic-act-9255
1.1.2 Registered births where the illegitimate children use the surname of the mother.
Who may file
Under these rules, the father, mother, child if of age, or the guardian, may file the public document or Affidavit to Use the Surname of the Father (AUSF) in order for the child to use the surname of the father.
Your annotated birth certificate with your father's surname will prove he is your father - then you can begin to gather your documents for their family visit visa.