Let me begin by saying that IMHO you might well accept adv.Linguado's proposal: archaic Italian is quite full of traps - (your former HELL is nothing compared to this...) - and enrolling the help of a native Italian speaker with the right cultural background can be a good way to go.

Anyway, more for fun than for anything else, I'm trying to offer a starting point.

You should construct the part from "confermando" to "presto" more or less as follows: "confermando (all the above) con un giuramento che qui io presto a mia delazione" - were "presto" is the present tense of the verb "prestare"; "prestare giuramento" means simply "giurare"; and "a mia delazione" should mean something as "under pain of denouncing myself for perjury".

The whole means something like "as sealed by my solemn oath, under pain of perjury to myself" - excuse my bad English, it's just to give you a hint.

I take that the following "e presta toccate le scrittura come di legge e pratica" ends with the name (or quality) of another person who also swears ("presta giuramento") as a witness.

Then, the rest is easy :-)

"toccate le scritture" means "with my hand on the Holy Writ" amd "come di legge e pratica" is something like "as the laws and usual practices request".

Thus the whole (from "confermando...") must be something on the lines of:

as sealed by my own solemn oath, under pain of perjury and confirmed by the oath of XX, made with our hands on the Holy Writ, according to laws and practices

Where XX is the person named or referred to at the end of the sentence (if my hypothesys is correct, of course)

As for Spanish, you probably know that a great part of Italy has long been under Spanish domination or influence, and a certain Italian penchant for orotund verbiage is commonly attributed to that influence (Personally, I suspect it was a 2-way exchange, though...)

:-)