install procedure confusion

[Hamster]

Hello,

I am trying to install mantis-1.1.0rc1 onto a Kubuntu linux server running apache 2.2.3 and php5.2.1.

I've proceeded far enough in the installation process that I have admin/install.php loaded in my browser. I've filled in the fields and have clicked Install/Upgrade Database.

For the database username I choose "mantis". I assume that this username is the one that the mantis php website uses to connect to the mysql backend (please correct me if I'm wrong!).

Now the confusion begins.

I get a line of "good" for the first lot of results:

Setting Database Hostname GOOD
Setting Database Type GOOD
Checking PHP support for database type GOOD
Setting Database Username GOOD
Setting Database Password GOOD
Setting Database Name GOOD
Setting Admin Username GOOD
Setting Admin Password GOOD
Attempting to connect to database as admin GOOD
Checking Database Server Version
Running mysql version GOOD

I also get a GOOD for the create database:
Create database if it does not exist GOOD

But the next line tells me:
Attempting to connect to database as user POSSIBLE PROBLEM
Database user doesn't have access to the database ( Access denied for user 'mantis'@'localhost' (using password: YES) )

Using the mysql shell I've looked at the mysql.user table and indeed the user "mantis" has not been created, so the acceess denied makes sense.

So here's my confusion. I've given the mantis installer the mysql root username and password. Why doesn't it create the mantis user and apply the correct GRANT statements?

Why is there no mention anywhere in the documentation that you need to manually create that user and apply the appropriate GRANT statements?

Or am I actually doing something wrong?

Because the documentation is rather sparse on the installation procedure, I'm really not sure if the problem lies with me or with install.php.

Can anyone help clarify just who needs to do what in order to get a working mantis install?

Thanks in advance.
Hamster.