Dario,
What everyone on ML is referring to is the mistake of calling this vehicle the Sd.Kfz. 251/17 Ausf. C. The vehicle does exist, your second link shows it and one of the responders tells you which book to get as well:
"Why do we keep refering to this vehicle as a Sd.Kfz.251/17 when it is a special series mounting the 2cm Flak 38 produced for the HG!
Now a days there is ample proof that the designation Sd.Kfz.251/17 Ausf.B was reserved for the SPW variant equiped with a special Schwebelafette mounting a 2cm Kw.K 38. The other variant was Sd.Kfz.251/17 Ausf.A which was to have the same 2cm Kw.K 38 mounted in the Haengelafette. Please read your Panzer Tracts No.15-3 if you don't want to take my word.
We really do need to question more to improve the standard of our hobby. Does anyone else agree that sloppy out of date names are no longer acceptable."
I mentioned the same thing in my Sd.Kfz. 234/2 review which is a vehicle that many still refer to as the Puma when it never officially had that name (and German veterans did not record that name in any of the known diaries). Again, there are Dicker Max and Sturer Emil, names not officially given to those vehicles:
"Panzerjaeger-Abteilung (Sfl.) 521's commander, Oberleutnant Kurt Hildebrandt relates that the two 12.8cm Sf. were called Max and Moritz by the troops while the only surviving 10.5cm Sf. was called Brummbaer." - Panzer Tracts No. 7-3 Panzerjaeger (7.5cm Pak 40/4 to 8.8cm Waffentrager) development and employment from 1939 to 1945 by Thomas L. Jentz and Hilary L. Doyle."
Regards,
