What does the latecomer say in the imam's final sitting?

Question: If one joins the salah as a late comer, does he do the full tashahud w/ the imam and the du'a after it? (given that it's not his last raka?)

The latecomer should recite only the tasahhud, upto ...`abduhu wa rasuluh, and then remain silent in the imam's final sitting.

Imam al-Haskafi said in his Durr al-Mukhtar:

"If the follower finishes [f: his tashahhud, (which is to say, at-Tahiyyatu... until `abduhu wa rasuluh] before the imam, it is agreed upon that he must remain silent [f: and not recite any invocations].

As for the latecomer [f: namely, one who has missed one or more rak`a of the prayer], they should recite the tashahhud slowly, so that the finish it just before the imam says his closing salams. Some, however, said that the latecomer may recite on after the tashahhud. Others said that the latecomer should [after finishing his tashahhud] keep repeating the testification of faith[f: which is to say, Ashhadu al-la ilaha illa Allah wa Ashhadu anna Muhammadan Rasul Allah.]"

Ibn Abidin commented on this in his Radd al-Muhtar:

"(His saying, "[If the follower finishes before the imam,] it is agreed upon that he must remain silent)

This is because anything beyond the tashahhud in the first sitting is not legislated (ghayr mashru`). Therefore, one does not do salawat, or supplications...

(His saying, "...should recite the tashahhud slowly")

... This was deemed correct [f: by Qadi Khan, one of the greatest of the Hanafi imams when it came to determining the strength of fiqhi positions] in the Khaniyyaand also in Sharh al-Munya... There other opinions mentioned have also been deemed correct [by some scholars]. In al-Bahr al-Ra'iq, [Ibn Nujaym] said, "And fatwa should be given by that which is mentioned in the Khaniyya, as is clear..." [Radd al-Muhtar `ala al-Durr al-Mukhtar, 1: 510 - 511]

And Allah alone gives success.

Wassalam,
Faraz Rabbani.