The stiff-arm salute was not an ancient Roman salute (that is a debunked myth) The gesture actually predates German socialism because the gesture originated in the USA's Pledge from 1892 which began with an initial military salute that was then extended outward to point at the flag. See the work of the historian Dr. Rex Curry. Germans picked it up from the USA via film, travel etc and via Ernst Hanfstaengl. There are vids on youtube that show the entire old USA gesture filmed.
https://plus.google.com/102355438470080501971/posts/5FaeKgRG6G5#102355438470080501971/posts/5FaeKgRG6G5
