This is possible although no trivial.
Your wnos.ini could look like this:
SignOn=yes
DefaultUser=myuser
Password=hispassword
But, as WTOS does not have any local users you will have to create a subfolder beneath ftproot/wyse/wnos called /ini. Then put a textfile in there named myuser.ini.
The password of the user has to be in the first line. You can generate the encrypted password using ConfGen (General 3 tab).
Give a try and play around with it a bit. I really do not know if a simple notice file is worth going this way, but it depends on your needs, of course
CG