Hi Wladmir;
Check whether any external alias is created for ushell service.
In SICF service itself, you have an option to see the external aliases.
Also,Try giving some other class name like "CL_ICF_SYSTEM_LOGIN" and see whether this takes any effect.
Also check the sicf settings for the service "arsrvc_upb_admn".(launchpad designer)
Regards,
Sarbjeet Singh