When I was looking for family members Births in Samoa I looked to this film. Maybe this may help you in your search.
Film number 1130493 Five items are on this film:
Item 1 Birth registers for Upolu, Western Samoa, 1905-1992 Upolu (Western Samoa). Civil Registry Office
Item 2 European birth registers, v. 1-55, 1920-1962 Western Samoa. Registrar General
Item 3 Births within the district of the British Consulate at Samoa, 1852- 1915 Great Britain. Consulate (Apia, Western Samoa)
Items 4-5 Register of British subjects residing in the Samoan Islands, ca. 1878-1915 Western Samoa. Registrar General
Items 6-8 Birth registers, 1876-1920 Western Samoa. Bezirksrichter
This film is from the Family History Library Catalog. Link here.