It is narrated from Sayyiduna Ibn Umar (may Allah be pleased with them both) that the Prophet (peace and blessings be upon him) used to separate the Witr and the two rak'ahs by saying salam, and the sound of the salam would reach our ears.
Hadith Referenceمسند احمد / مسند المكثرين من الصحابة / 5461