east european chars not working

Hi,

I use prawn to generate invoices in local languages for nine
countries. When generating pdfs for Latvia and Lithuania some chars
get substituted with underscores. These are chars like: ē.ķ.ą, That
is: 271 e with macron, 302, k with ogonek the other way (?), 263 a
with ogonek. There might be more.

I run the system on Snow leopard server, the chars are all available
in the system Helvetica. Rails 3.0.7, ruby 1.8.7.

Anyone knows how to sort this out?

thanks!