I can find nothing in the documentation that suggests or states that you can use anything other than the three usual (num pad insert, regular insert, caps lock) choices as the NVDA modifier key.
Are you positive that you cannot tweak vmWare fusion?
Brian Version 1703, Build 15063.296, Home 64-bit
Travel is fatal to prejudice, bigotry, and narrow-mindedness, and many of our people need it sorely on these accounts. Broad, wholesome, charitable views of men and things cannot be acquired by vegetating in one little corner of the earth all one's lifetime.
~ Mark Twain