A question about "Timestamp" and "Created Time"

[Eduardo <dutche@gmail.com>]

Hi, I have a FTP server that is outside my company and the users on my
network (inside the company)  must put their files at this FTP vwith
the help of a NFS mounted directory that I shared with SAMBA.

But when anyone puts a file in there, or even if I transfer the file
using SFTP, the "Created Time" attribute changes to the current date.

And when anyone puts a file via FTP, the "Created Time" changes too.

Does anybody knows how can I keep it to original??

Thanks