Configuration For Firebug Message Logging

Hi,
I have the following settings for activating Firebug in the 'components'> 'log' > 'routes' section of the configuration file:

array(
// settings for profiling messages of any category, to be captured in Firebug
'class'=>'CWebLogRoute',
//'levels'=>CLogger::LEVEL_PROFILE,
'levels'=>'profile',
'showInFireBug'=>true,
'ignoreAjaxInFireBug'=>true,
),

In the controller I have these statements:

Yii::log('This is a profile message', CLogger::LEVEL_PROFILE, 'profile');
// example from the cookbook
Yii::beginProfile('This is a test for the profile logging: start profiling', 'first profile category');
for ($i=0; $i<10000; $i++) {
preg_replace('~^[a-z]+~', '', 'test profile');
}
Yii::endProfile('This is a test for the profile logging: stop profiling', 'first profile category');

Besides the Firebug config I have all the others - email, files and browser - which work fine; the browser logs the controller's statements above too. But in Firebug I have the Console tab empty, both as menu and as content; note: I have set the 'levels' in both ways and got same result (i.e. none).
I'm new to Yii, although quite skilled in programming, so thanks for your hints.