Don’t worry, Luis. It’s not just you. This sounds strange to everbody’s ears. :)
It is possible to use the same as a substantive instead of as an adjective. However, it is in my opinion not necesssarily advisable outside of specialized fields like law and linguistics.
Here are the two main substantive possibilities:
- Used absolutely (that is, without a noun following it, so a nominalized adjective) as in the same, it acts like a noun. It takes a definite determiner, but does not normally admit a plural inflection. (But see sense 5b below.)
- Used as a pronoun, it means it, and so being a pronoun takes no determiner there.
It’s a very old way of speaking that today is found almost only in legalese, but from which it seems to have been snatched up by the captains of commerce to make them sound fancier. This is usually gratuitous; for example, in your second sentence, I would advise using this there instead of the same.
This all is covered by the OED entry for same in sense 4a under section B:
B. absol. and as pron. (Constructions as in A.)
4a. the same, † that (or this) same: the aforesaid person or thing. Often merely the equivalent of a personal pronoun; he, she, it, they. Now rare in literary use; still common in legal documents; also (with reference to things) in commercial language (where the is sometimes omitted).
And here are some of its citations showing this sort of thing:
- 1819 Keats Isabella ii, ― Her lute-string gave an echo of his name, She spoiled her half-done broidery with the same.
- 1901 M. Franklin My Brilliant Career viii. 56 ― A big red-bearded man··had received a letter from Mrs. Bossier instructing him to take care of me. He informed me also that he was glad to do what he termed ‘that same’.
- 1926 in H. W. Fowler Mod. Eng. Usage 512/1 ― Sir,-Having in mind the approaching General Election, it appears to me that the result of same is likely to be as much a farce as the last.
- 1966 G. W. Turner Eng. Lang. in Austral. & N.Z. vi. 135 ― A different influence of written language is seen in the use of same as a pronoun equivalent to it, as in ‘put the tailboard up and secure same with a length of wire’ from New Zealand (Wally Crump, 1964), a facetious borrowing of lawyer’s English which is quite common.
- 1973 N.Y. Law Jrnl. 24 July 4/4 ― The following sentence in a brief is typical of its misuse as a noun: ‘Waldbaum purchased the soda··then stacked it on the shelves in order to sell the same.’
As you see, it is not especially well looked upon in some of those citations.
However, using same that way is quite different from the specialized linguistic use of sames, which per the OED means, with two recent citations included:
5b. pl. Linguistics. Features or utterances that are identical.
- 1964 Crystal & Quirk Syst. Prosodic & Paralinguistic Features in Eng. iv. 49 ― We should··only subsequently look for the correlations between postulated ‘sames’ of tension and formal items in the linguistic and situational context which will enable us to make statements of meaning.
- 1977 Trans. Philol. Soc. 1975 9 ― Certain configurations in languages typically result from the principled (‘lawful’) divergence over time of original sames.
It sounds more than a little bit stodgy and snooty, like someone is putting on airs. I would be chary of using it in any situation in which that were not the intended effect.