Special characters in search bar

Could someone please help me how to enable OC to search for special characters such as á, é, ó etc?
It seems if I use these characters in a product's name, the search module won't find it.
I also found an OC webshop where these character searches work: http://www.conasinf.com/index.php?route ... %C3%A1fico
I found this thread but didn't help: http://forum.opencart.com/viewtopic.php?f=20&t=18416
Thank you.

Maybe this can help you

http://support.themeburn.com/topic/sear ... post-14067

Thank you Finezze, I'll check that XML modification.