These are just my thoughts as I said I am no expert in this matter.
The Quran and Hadiths are clear that it is a must to recite Quran in Salah.
The Quran in its original Arabic is the word of Allah, and if we accept that translations of the Quran would not be considered actual Quran, then we wouldnt be fulfillling the obligation of reading Quran in Salah (as demanded by Quran and Hadith) by reading translations.
So what should a person do in the meantime ?
The hadith was already quoted by abumuhammad wherein the Prophet Salalahu alayhi wasalam moreorless says to read what Quran you have memorized in Salah, and if you dont know any Quran then read alhamdulilah, Allahu Akbar and la ilaha ilalah and then bow.
That should address the query about reading Quran in Arabic in salah.