And i finally found the solution...

I knew it was using userdata, but the syntaxes "userdata" "userData" and many other things wasn't clear for me.

So in fact, jsonreader isn't necessary and you only need to set an array called "userdata" in your json response with your data inside.

Now let's find how to manage buttons.

Now my "problem"...

In my json returned data, i get a variable that i would like to use to hide/show some buttons in the toolbars because it's a filemanager and i need to manage permissions ( "Add file", "Delete" , ... buttons )

But using getGridParam i can't read it as i do for "page" "records" or all other standard variables.

The datatype is json and i use the colModel way to define ( not jsonreader , maybe i don't understand enough... )

So if anyone could push me some idea to know what i'm doing wrong...

Thanx in advance.