On a RHEL system set to a Spanish locale, vsftpd lists directories in English

Issue

• Using the default ftp server "vsftpd", with Spanish locale, the directory listing from the command "ls -l" within a ftp from a client, comes out in English instead of Spanish.
• When we make an FTP connection from a client and execute an "ls -l" command, the result of directory comes out in English instead of Spanish. In particular, and as an example, the name of the month of April comes out as "Apr" rather than "Abr", and "Jan" for January, instead of "Ene". The server is generated with the Spanish locale (LANG = en_US.UTF-8).