Alpha and Beta Print

Hello,

 

I've got a a little problem with the printing of the alpha and beta
characters.

I am generating PDF-reports from a webinterface with XML and XSL-FO.

On this reports are the Characters "Alpha" and "Beta" from the Greek
alphabet.

But if I print this form, then the Greek chars turn into # . Why?

 

Thanks for help!

 

Michael