I also pray 3 rakas of witar but i make it different from salat al maghrib by raising hands for takbir before dua e Qanot.Is it correct?.
Before answering this question, we would like to say that we appreciate your eagerness to follow the Sunnah, and we ask Allaah to make us and you among those who listen to the word and follow it properly.
What you have said – may Allaah guide you – about not wanting to make Witr resemble Maghrib by raising your hands for the Takbeer before reciting Du’aa’ al-Qunoot, is not what is meant by the prohibition of the Prophet (peace and blessings of Allaah be upon him) in the hadeeth narrated by al-Haakim (1/304), al-Bayhaqi (3/31) and al-Daaraqutni (p. 172), and which was classed as saheeh by al-Haakim according to the conditions of al-Bukhaari and Muslim. According to this hadeeth the Prophet (peace and blessings of Allaah be upon him) said: “Do not pray Witr with three rak’ahs that resemble Maghrib.” What he (peace and blessings of Allaah be upon him) meant, as the scholars have explained, was that we should not sit to recite the first Tashahhud in a manner that resembles Maghrib.
See Fath al-Baari by Ibn Hajar, 4/301. al-Haafiz said: Its isnaad is saheeh according to the conditions of al-Bukhaari and Muslim. See also ‘Awn al-Ma’bood, commentary on hadeeth no. 1423; Salaat al-Taraaweeh by al-Albaani, p. 97.
Raising the hands for Takbeer before reciting Du’aa’ al-Qunoot makes no difference in fact, because there are four places in which the hands should be raised during prayer:
1 – When saying Takbeer al-ihraam (takbeer for starting the prayer)
2 – When bowing in rukoo’
3 – When standing up from rukoo’
4 – When standing up after the first tashahhud
It is not prescribed for the worshipper to raise his hands at any point other than these four.
See Fataawa Arkaan al-Islam by Shaykh Muhammad ibn ‘Uthaymeen (may Allaah have mercy on him), p. 312
And Allaah knows best.