Form validator rule alpha and UTF-8

[eluser]davlyn[/eluser]
When I set the alpha validation rule for a input field in my form and when I type characters like ŠĐČĆŽ etc the rule doesn't see those characters as letters. I use a database that has UTF-8 encoding. How do I modify the regex ( "/^([a-z])+$/i" ) to include those letters?

EDIT: I can do it with "/(*UTF8)^([a-zšđčćž])+$/i" . Is there a better solution?