friendly_id questions

Hi everyone. I'm starting a project, and I'm now using friendly_id
plugin to fetch "estudios". I've got two questions:

1. It acts weird with accented i. If I have an estudio "ÁÉÍÓÚ", it
shows:
     http://localhost:3000/estudios/áéíóú
   Why isn't it working?

2. Is there a way to have custom slugs? Could an "estudio" edit it's
own slug,
   instead of being only generated from it's name?

Thank you in advance;

Eugenio.