Friends if you remember I said that I had my son's partial custody?

which said that I cannot take him out of my country on a permanent basis.A recent development has taken place, from the family court, the judge wrote on an exclusive family court legal valid doent that " I, the mother, has my son's custody& guardianship and this guardianship/custodianship will always remain with me and that the father will never ever in future claim my son." This was signed by my ex and myself at the court before the judge. Is this doent sufficient and will I be able to get a visa for my son and if I decide to settle in Canada or USA, will I be able to or I will still need my ex husband 's permission ( to take my son there )? Please help as before also there was an angel named Thang who really really helped and supported. Help???