[Zope] Generic User Folder - custom user properties

[Michal Bukovjan]

I have (I hope) simple question :

I use Generic User Folder for authentication of users against Postgress
database.
I rewrote the appropriate DTML methods, and it works.

However, with the AUTHENTICATED_USER, I only get the name of user, its
roles and domain.
I need to associate another attribute/property, called 'user_id', which
is an integer value of the user's record in the database. The value
should then be used in subsequent SQL queries on behalf of the user.

My question is, if it is possible (so that I can then call
"AUTHENTICATED_USER.getProperty('user_id')") and at which point of
Generic User Folder/authentication process I should assign the property
value?
Is there an easy way?

Thanks,

Michal Bukovjan