Two Rak'ah Sunnah before fajr

Do you recite loudly or silently in the two Rak'ah Sunnah which you pray before the fajr prayer?

One group has said you recite silently based on the following hadith:

It was narrated that Aishah said:

"I would see the Messenger of Allah (sallallaahu alayhi wa sallam) praying two rak'ahs of Fajr and making them so brief that I said: 'Did he recite the Umm Al-Kitab in them?'"

[Sunan al-Nasaa'i Hadith No. 946]

The evidence is that had he (sallallaahu alayhi wa sallam) recited loudly then she (may Allaah be pleased with her) would have known how much he (sallallaahu alayhi wa sallam) recited.

The second group says that you are to recite loudly based on the following hadith

It was narrated from Abu Hurairah that:

The Messenger of Allah (sallallaahu alayhi wa sallam) recited: "Say: O you disbelievers" and "Say: He is Allah, (the) One" in the two rak'ahs of [the Sunnah of] Fajr.

[Sunan al-Nasaa'i Hadith No. 945]

The evidence is that Abu Hurairah (may Allaah be pleased with him) could have only known which Suurah were recited had he (sallallaahu alayhi wa sallam) recited out loud.