What does our Prophet mean here! Explanation of the Hadith: Bukhari, Volume 8, Book 73, Number 53, Al-Adab

The hadith says: > " A group of Jews entered upon the Prophet and said, > "As-Samu-Alaikum." (i.e. death be upon you). I understood it and said, > "Wa-Alaikum As-Samu wal-la'n. (death and the curse of Allah be Upon > you)." Allah's Apostle said "Be calm, O 'Aisha! Allah loves that on, > should be kind and lenient in all matters." I said, "O Allah's > Apostle! Haven't you heard what they (the Jews) have said?" Allah's > Apostle said "I have (already) said (to them) "And upon you ! " Here when our Prophet (saw) says "And upon you" what does he exactly mean here... just like how the arrogant jews says "Death be upon you" does our Prophet mean the same back at them. If yes, wouldn't it contradict when he said "Be calm, O 'Aisha! Allah loves that on, should be kind and lenient in all matters." If yes, does it question the integrity of the hadith. Please can someone help me understand. Jazakallah