Birth certificate validity

If I may, I have a different question and Iā€™m hoping to get advice from someone who has direct experience. I am a naturalized Venezuelan citizen applying for Portuguese citizenship. To make a long story short, I would like to submit a birth certificate issued by my country of birth, where I am currently residing, but my lawyer insists that the birth certificate must be issued by my country of citizenship, which for inexplicable reason looks like will cost me 2000-3000 dollars to obtain! Is it really the case that I must submit a birth certificate issued by my country of citizenship or can I submit a certificate issued from the country that I was actually born? Thank you for sharing your experience.