Question: I found a 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''
Why we Hanafees still insist in praying the Witr 3 rakah like the Magrib if the prophet has prohibited to do so?
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.
Answer: You should understand that Abu Hanifa is not a student of al-Haakim, Al-Bayhaqi, al-Daaraqutni, Al-Bukhaari or Muslim and isn't obliged to follow their views. In fact he Abu Hanifa passed away before any of these scholars were born. It is very important that you realize that one of these scholars saying a hadith is sahiih does not mean that a mujtahid is obliged to go by its apparent meaning. Saying a hadith is sahiih is a matter of ijtihaad -an opion of these scholars. Mostly all it means is that the chain of narration is sound. Whether the meaning is sound and required to be followed is something else. Mayby Abu Hanifa did not see this hadith as sound, maybe he took it as a figure of speech, maybe he saw it as abrogated. This is how you should think when exposed to these questions.
In any case, if the meaning was apparent then the answer is that hanafis don't pray it like Mahrib, because they add qunuut. Moreover, Prophet Muhammad has prayed witr 3 rakaah without tasleem on the second as stated by Ibn Hazm. Another possible meaning of the hadith is to say that it means that you should add at least 2 or more rakaahs before it from the night prayer, and not just pray witr.
