La Repubblica has an article about the fake Nigierien dossier.

This is absurdly obvious forgery which purported to show that Iraq had sought to buy 500 tons of yellowcake from Niger. The story first recalls that the dossier passed through the hands of Rocco Martino, an ex officer in police/military intelligence who was fired for misconduct in 1977 but kept contact with Italian intelligence and, in particular, SISMI (roughly the Italian CIA). This is well known since he sold the dossier to Elisabetta Burba an journalist at the weekly "Panorama" who gave a copy the the US embassy and also investigated the story and concluded that the dossier was bogus. To be as polite as possible Panorama does not have the highest journalistic standards in the world, so the fact that the President of the USA went with something too dubious for Panorama caused great hilarity in my family. Oddly CARLO BONINI e GIUSEPPE D'AVANZO don't mention Panorama, and, in fact, say the dossier was passed directly from SISMI to the embassy.

Bonini and D'Avanzo report that Martino was helped in forging the dossier by Antonio Nucera vice director of the Sismi office in viale Pasteur Rome. Josh Marshall confirms that Nucera was involved, although he and co-authors did not publish the name referring only to "a SISMI agent".

Bonini and D'Avanzo go on to claim that Martino and Nucera were assisted by a woman who's name they do not report who works at the Nigerien embassy in Rome and who agreed to be interviewed. Marshall et al also mention a woman whose identity they shield.
Bonini and D'Avanzo further claim that the three obtained the assistance of the "primo consigliere" of the embassy Zakaria Yaou Maiga (I'm not sure if that is Italian for charge' d'affairs). I think this accusation is new.

Bonini and D'Avanzo report a novel explanation of the whole plot. They say that the original plan was to sell the dossier to the French who were concerned about smuggling of Nigerien Uranium, and that the dossier was, indeed sold to the Direction Générale de la Sécurité Extérieure. An un-named DGSE agent says that they immediately recognised that the obvious forgery was an obvious forgery since the dossier presented a long since retired foreign minister (Allele Habibou IIRC) as foreign minister at the time of the alleged deal. Getting the signature right is level one forgery. Getting the forged name right is level zero.

Then, they claim, after 9/11 the new head of SISMI's WMD branch Alberto Manenti askes Nucera (who was about to retire) to stay on as a consultant. Anonymous sources blame the head of SISMI Nicolò Pollari.

The extremely unreliable Rocco Martino is quoted as saying "Alla fine del 2001, il Sismi trasmette il dossier yellowcake agli inglesi del MI6." That is, "At the end of 2001 SISMI transmitted the yellowcake dossier to the English, that is, MI6"

dando pane per focaccia (tit for tat in Italian) Pollari said "Seguivamo Martino e avevamo anche le foto dei suoi incontri a Londra. Volete vederle?". 'We followed Martino and whe have photographs os his meeting in London. Do you want to see them ?" That is, Martino gave the dossier to MI6.

The one good source Bonini and D'Avanzo seem to have is Greg Thielmann at the State Department's bureau of intelligence and analysis. Translating Theilmann back into English I get "I received a report in fall 2001. It was a synthesis that Langley received from its field officer in Italy. The field officer reports that Italian intelligence showed him some papers which document the Iraqi attempt to buy more than 500 tons of pure Uranium from Niger."

This does suggest direct official SISMI involvement.

Doubts are raised by the assertion that more confirmation is provided by the fact that Wilson was sent on his mission. It is generally reported that Wilson was sent before US officials got news of the dossier. Actually, I guess, it is possible that he was sent after a CIA agent saw the dossier but before the dossier arrived in Langley.

Josh Marshall warns that, in his experience, when any facts emerge in Rome they are immediately obscured in a cloud of leaks, innuendos and lies. This corresponds to my experience in reading Italian newspapers. I agree that it is a standard operating procedure for Italian politicians and institutions who want to obscure the truth to cover it with wild leaks.

In this case, as is typical for La Repubblica and, in particular, d'Avanzo, they are trying hard to fight the spin arguing that SISMI as an institution deliberately misled the CIA "il Sismi affida quelle informazioni, che sa essere false, alla Cia"
SISMI sent that information, which it knows to be falsee, to the CIA." Unfortunately the spin vs counterspin struggle arrives at the truth only by accident, so I tend to agree with Marshall who suggests we take it all with a grain of salt.