we want to replace params-array from application/config/internal.php but values will be merged

As to clarify, what do you mean by merged?

adding this to config.php, it results in the grafic

'params' => array(
        'defaultPageSize'=>20, // Default page size for most of the grids
        'pageSizeOptions'=>array(10=>10, 20=>20, 50=>50, 100=>100, 250=>250, 500=>500), // Default page size options for most of the grids
        'pageSizeOptionsTokens'=>array(5=>5, 10=>10, 25=>25, 50=>50, 100=>100, 250=>250, 500=>500, 1000=>1000, 2500=>2500, 5000=>5000, 10000=>10000), // Tokens needs different options
        'defaultEllipsizeHeaderValue'=>30, // Default max characters before ellipsizing the headers of responses grid
        'defaultEllipsizeQuestionValue'=>50, // Default max characters before ellipsizing the questions inside responses grid
    ),

grafik.png (13,581 bytes)   

grafik.png (13,581 bytes)   

Ohh, I see.

I believe the simplest is to create a new file "config-after.php", which holds a function which shall be called as a hook to update as much as wanted the final config array.

Not sure how spreaded this problem is.

The function could be an item of the config array itself and be addedd to the config.php

Thoughts on the approach?