It is pronounced more like this...WAH'-shung, with the accent on the first syllable with a "short" A sound, not a "long A" sound...like saying wash, just without the SH sound being there on that first syllable...Your Chinese sister in law is adding something more to that word which may have more meaning to a fluent speaker of the language, but not as far as the name of the corporation is concerned...DAMIEN
Ps...YES, I was a "victim" of a classical education...lol.
I believe the correct pronounciation is in Cantonese dialect for "Huasheng", not Mandarin dialect...What dialect does your sister in law speak as there are many different dialects in China depending where one is from?