user authentication

Hi, i'm sure that it's a stupid question but i would like to have your feedback on it. i have MySQL with 2 users in the "mysql" database which are root and uimmense. i suppose that what i see in the password field is the sha1 crypted password. is it correct or not ? but lets continue... in fact, my web application should use a database named "immense". in this database, there is a table named "profiles". in this table, the login "uimmense" and its MD5 password are stored. the problem is : when i use mysql_connect('localhost','uimmense',myMD5password); to connect to MySQL database system, the connection is refused because the MD5 password does not correspond to what is saved into users table within mysql database... :-( here is my question : all my users registered into my "immense" database, should be also registered as users of MySQL database system ? (which is stored into "users" table, into "mysql" database) ? is it clear ? i do not see really realistic if everytime that a new user is registered to my application, i have to create him a profile for MySQL database. thanks a lot, Alain