Is it violation of our constitution?

O.H. Kabir, Dhaka
Prime Minister Sheikh Hasina took salute at the Victory Day parade at the National Parade Square on 16th December 2012 as President Zillur Rahman was ill and set to leave for the UK for treatment. Traditionally, the president takes salute on Victory Day and the prime minister observes it as a guest. Article 54 of our constitution clearly says, "If the president is unable to discharge the functions of his office on account of absence, illness or any other cause, the speaker shall discharge those functions.” Why was the speaker barred from taking salute at the great national event of Victory Day parade and under what authority the prime minister performed the duty of the president? Is this a violation of our constitution or not? Would our constitution and legal experts kindly enlighten us on the matter?