a rough collection of sources
Bibliographic information
Quote 1
Page 13 extract In October, 1776, an American schooner carrying this flag had her colors saluted at the Danish island of St. Croix, which seems to have been the first salute from foreign guns.

This flag was saluted November 16th 1776 by the Commander of “St. Eustatius,” in the Dutch West Indies, .. ..

Title The Birth of Our Flag, and Flag Etiquette: An Address Delivered Before the Pennsylvania Society of the Order of the Founders and Patriots of America Author Louis Barcroft Runk Contributor Order of the Founders and Patriots of America. Pennsylvania Society Publisher J.B. Lippincott Company, 1921 Original from the University of Michigan Digitized 3 Jun 2008 Length 32 pages

Quote 2
http://webpac.uvi.edu/imls/pi_uvi/profiles1972/Patriots/Markoe_A/text.shtml
The above link is an article in English about a Dane from St Croix who designed the first American flag.

Quote 3

http://www.americaslibrary.gov/jb/jazz/jb_jazz_virgin_3.html
U.S. Took Ownership of the Virgin Islands March 31, 1917 Even though Denmark was an officially neutral country during the American Revolution (it was neither on the side of the Colonies nor the British), there was one case of arms and supplies smuggled to the Americans from the island of St. Croix. The Interior Department report states that, as the supplies were being passed, salutes were exchanged "between a merchantman flying the Grand Union flag [America's flag] and Fort Frederik at the west end of St. Croix." Their salute was "the first acknowledgment of the American flag from foreign soil."
Quote 4
St Croix Landmarks
Fort Frederik, begun in the 1750's, is a National Historic Landmark. In 1776 the first salute from foreign soil to the new national flag of the United States was fired here.
Quote 5
http://da.wikipedia.org/wiki/Frederiksted in Danish

Danish Wikipedia uses Quote 4 above
Quote 6
"The First Salute: A View of the American Revolution" by Barbara W. Tuchman.
Her title refers to the return of a salute from the Dutch island of St. Eustatius to the American Brigantine "Andrew Doria" on 16 November 1776 as the first salute to the American flag by a foreign countryTuchman, in her book, acknowledges that there were several "first salute" claims but bases her book title on one fact.
In 1939, President Franklin Delano Roosevelt presented a plaque to St. Eustatius. Mounted on the ruins of Fort Orange, it reads, "In commemoration of the salute of the flag of the United States fired in this fort November 16, 1776 by order of Johannes de Graff, Governor of St. Eustatius in reply to a national gun salute fired by the U.S. Brig-of-war Andrew Doria.. Here the sovereignty of the United States was first formally acknowledged... to a national vessel by a foreign official."
Quote 7
Saint Croix 1770-1776: The First Salute to the Stars and Stripes
Robert Amandus Johnson chronicled this period of the history of Saint Croix from 1770-1776 and the remarkable relationship of the Island to the emerging American Nation. It relates, what is believed to be, the first foreign recognition of the American "Stars and Stripes." This occurred in Christiansted, St Croix in June 1776, prior to Congressional approval of the Declaration of Independence. This early "Stars and Stripes" was being flown from the American Brig "Nancy." The American Revolutionary Financier, Robert Morris had chartered the Brig "Nancy," on behalf of Congress, to acquire critically needed gunpowder in the Danish West Indies. Mr. Johnson resides in St Croix, U.S. Virgin Islands, his adopted home since first arriving as an Ensign in the U.S Navy in 1959.
Quote 8
Andrew Doria - The First Salute, Inc.
This is the site of a Company dedicated to bringing an important part of the early history of the United States before the public in a material and dramatic manner.
(In reply to a question from Viking1808, they write )What I do know is the US Navy publications and the Dutch Government all have records indicating the First Salute took place on Statia on 11/16/1776. Please share new information at your disposal. Send it to the Company email: adtfs@baybroadband.net I will try to track down the reference you mentioned. Thank you, Joseph D. Irr, President Andrew Doria - The First Salute, Inc.