remove last login information from zenwalk start-up

I have a new toy called Zenwalk and I'm using auto-login as usual for buying some time. But there's something bothering me with my new toy; in every boot, it shows me my last login's time and date and there's no way to get rid of this thing through zenwalk's settings. For removing this annoyance, you have to follow these steps:

1. open Terminal
   
2. type

   su
   

   and login
   
   
3. type

   mousepad /etc/pam.d/system-auth 

   and add

   #

   to the beginning of

   session    optional   pam_lastlog.so

   line.
   
4. save and quit mousepad