Now I found the way to receive Tab forms through function saveEditTab($tab, $user, $ui, &$postdata)
To be clear let's say I have a tab with 2 fields declared by the plugin in xml file. One text that I fill through getEditTab and a yes/no radio button that the user can set to accept the text I submitted.
I receive the correct setted form in $postdata but when saveEditTab returns they are set to the original values that are tooken from database at getDisplayTab call. Same with $user whitch contains same fields.
More, if I directly set the fields in the database through saveEditTab I see them changed in that database with phpmyadmin but when I let the function continue and return they are resetted again by CB.
Am I miss using those functions ?
Should I try onBeforeUserUpdate event or something else ?