As-Salam Aleikum wa rahmatullahi wa baraketuh,
absolutely correct brother submit, in Isaiah 42 there is no mention about the Romans, nor Greeks, it specifically speaks about the Arabs, but the new song is not about the Quran as some Muslim scholars have claimed. Believe me, the true interpretation is far from currently maintained views (yet, still in a positive manner). I cannot tell you the details now, since it would spoil a surprise which I 'am preparing for all of our Muslim brothers and sisters, as well as for our Christian friends. I hope insha'Allah my book will revolutionize the way of interpreting prophecies concerning Prophet Muhammad (pbuh) in the Bible, and will open the heart of many people leading them to Islam by the will of Allah! Ameen ya rab!
Take care, and Salam
Ahmed (Poland, Warsaw)