@StefanGr
Key is to modify it in plugins.
This is part in theme: osc_run_hook('user_menu');
If you see in plugin osc_add_hook('user_menu', 'some function'), you can add 3rd parameter as "priority" (1-10).
osc_add_hook('user_menu', 'some function A', 1)
osc_add_hook('user_menu', 'some function B', 10)
function A will be executed prior to function B.