We get the regular user info from the vb
user table. I know of no access from our program to any usercss table.
The buyemail though is STORED in the classifieds users table which for you is cp_users maybe. Like I said we explicitly store and retrieve that value from one of our tables has nothing to do with vbulletin in any manner.
You can send info for me to look at things be nice to see what is in your database.