[otrs] Customers creates by postmaster not seen in AdminCustomerUser

Hi, I am new to OTRS, and after a lot of googling, I cannot find why what I'm trying to do does not work. I have set up ticket creation through email via pop3. That works fine. But the customer created via this process does not apper in the main customers list, so I cannot edit its information. What am I doing wrong ? Thanks, Thomas