Dought & clear - Ruling on zakaat al-fitr and how much is to be paid

Is the hadeeth "The fast of Ramadaan will not betaken up [to Allaah]
until zakaat al-fitr is paid" saheeh?
If the fasting Muslim is in need and does not possess the threshold
(nisaab) of zakaah, is he obliged to pay zakaat al-fitr because of the
soundness of this hadeeth or other saheehshar'i evidence that is
proven in the Sunnah?.
Praise be to Allaah.
Sadaqat al-fitr is obligatory upon every Muslim who is
self-supporting, if he hasone saa' or more than heneeds of food for
himself and his family onthe day and night of Eid.
The basis for that is the report narrated from Ibn'Umar (may Allaah be
pleased with him) who said: "The Messenger of Allaah(peace and
blessings of Allaah be upon him) enjoined zakaat al-fitr, a saa' of
dates, or a saa' of barley,upon all the Muslims, slave and free, male
and female, young and old, and he commanded that it be paid before the
people went out to pray." Agreed upon; this version was narrated by
al-Bukhaari.
And Abu Sa'eed al-Khudri narrated: "We used to pay zakaat al-fitrwhen
the Messenger of Allaah(peace and blessings of Allaah be upon him) was
alive, a saa' of food or a saa' of dates or a saa' of barley or a saa'
of raisins or a saa' of dried yoghurt." Agreed upon.
It is acceptable to give a saa' of the local staple food such as rice etc.
What is meant by a saa' here is the saa' of the Messenger of
Allaah(peace and blessings of Allaah be upon him), which is four times
the amount that may be held in the two hands of a man of average
build. If a person does not pay zakaat al-fitr, he is sinning, and he
has to make it up.
With regard to the hadeeth mentioned, we do not know whether it is
saheeh or not.
We ask Allaah to give you strength and to make our words and deeds and
yours righteous.
And Allaah is the Source if strength.