1. A method of processing uniform mailpieces or “runs”, in which, in a mail preparation zone ( 4 ), the mailpieces of a “run” are prepared in trays or on trolleys, and the prepared mailpieces are brought to the inlet of a postal sorting machine ( 2 ) for a first sorting pass, and in which the mailpieces are fed in series into the sorting machine ( 2 ) comprising a sorting conveyor ( 6 ) and sorting outlets ( 7 ), a digital image of each mailpiece is formed ( 30 ) in the sorting machine ( 2 ), and processing is applied to each digital image for automatically recognizing address information for the purpose of automatically directing ( 37 ) the corresponding mailpiece through the sorting conveyor ( 6 ) towards a determined sorting outlet ( 7 ) of the sorting machine ( 2 ), and in which a digital model of the run is built in a database ( 15 ), the digital run model being defined by data characterizing the graphical appearance of the mailpieces of the run and being associated in the database ( 15 ) with setting indications usable by the automatic recognition processing, said method being characterized by the following steps in advance of the first pass of the mailpieces of the run through the sorting machine ( 2 ): a) using an interactive acquisition terminal ( 9 ) that is located remote from the sorting machine ( 2 ) to form a digital image of a certain mailpiece of the run, said interactive acquisition terminal ( 9 ) comprising a scanner with a camera ( 10 ), a presentation stand ( 11 ) on which an operator places said certain mailpiece of the run flat and facing the camera ( 10 ) in order to input a digital image of the face of said mailpiece that bears a recipient address, and a man/machine interface with a display screen ( 12 ) and with a keyboard ( 13 ), which interface is connected to a data-processing unit ( 8 ) connected to said database ( 15 ); b) in the data-processing unit ( 8 ) and on the basis of this digital image, computing attributes or descriptors of the run so as to build ( 20 , 21 ) said digital run model in said database ( 15 ); and c) in said database ( 15 ), associating ( 23 ) said run model with said setting indications from said interactive acquisition terminal ( 9 ), said indications also being input from said interactive acquisition terminal ( 9 ).