Is it permissible to pray the Shaf' in the early part of the night with 'Isha and delay the Witr until the end of the night with the Qiyam prayer?

"Shahr (even) refers to what is prayed as two or more rak'ahs before Witr (odd). It is permissible for there to be a long interval between Shafi' and Witr, although it is preferable not to have one. It is not a condition to specifically intend the two rak'ahs of Shafi' with a separate intention; rather, it is sufficient for Witr to occur after any two rak'ahs. If the interval between Shafi' and Witr is long, it is not necessary to repeat Shafi' to complete Witr. However, if supererogatory prayers are offered before Witr after a long interval, they are considered a new Shafi'."