APEX

I am using custom authentication scheme for my application - user names/passwords stored in a custom table and it all works fine. There is now a need for me to let a "workspace user" access this application i.e there is no such username in my custom table. There is only one such user and the username is fixed. I just need to do something like this in my custom authentication function :-

if the username = my known workspace user then
call wwv_flow_security.authenticate(p_username,p_password)
else
check the username and password in my custom tables
end

Question 1: Is calling the authenticate function the correct way of authenticating workspace users ?
Question 2: Even though I pass the correct username and password, I still get invalid credentials. The password passed in is clear text, do I have to hash it before passing in ? If yes, then how ?

thanks in advance