The Italian copies of the Paterson powder charger were never made to operate like the originals. As has already been noted, they have no separate chamber for ball and powder. In addition the spouts on originals are fixed and the powder is dispensed by twisting the assembly to open a multi-holed trap door. The spouts on Italian replicas are instead the plunger type used in the larger single spout flasks made for the later Walker and subsequent Dragoons
What the Italians did was not even bother with trying to duplicate the original mechanics. Since they had already come up with tooling to make the plunger type single loading nozzle on the Walker and Dragoon type flasks, they just used five of those plunger style nozzles to replicate the look of a Paterson flask. Also, Individually those nozzles have pretty decent springs. Now multiply that by five and you will find it sometimes pretty difficult to effectively push the Italian version down to get an equal load.
There have been some replica flasks made that duplicate the original construction and operation, but they were costly. There was one such company in England that would supply flasks, molds, cleaning rods, and even the fancy snail type cap loader with the prancing pony cast in the top. These were used in some of the fancy cased sets sold by the US Historical society and such. However, the company is no longer making these accessories since the demand basically died. They are quite expensive when they show up occasionally in auctions.
The only reason for this type of loader in the first place was because the initial Paterson design had no loading lever nor any cap channel to put caps on the nipples. As designed, one was forced to have to pull the barrel and cylinder to reload. The idea was that if one was going to have to do that anyway, why not come up is a flask that could charge all 5 chambers at once.
One should note that toward the end of the Paterson production, a loading lever was added to the Paterson and a cap channel machined into the rear flash guard. From that point on, cased sets only came with a single nozzle push plunger flask--the nozzle working like those on the Dragoon flasks.
With the exception of the Baby Dragoon, all Colt percussion revolvers from that point on had built in loading levers and cap channels, eliminating the need to pull the barrel and cylinder to load and thus also eliminating any way to load using a multi-spout flask.
The only use for one today would be for those who load with one of the off gun loading presses, but those are a relatively modern black powder accessory.
Cheers