Character is square when print thai character

[Surachai Locharoen <surachai@prachakij.com>]

I install debian testing from ftp.us.debian.org. I want to print html 
file from mozilla-firefox such as www.google.co.th. I choose menu 
file>print and select "print to file" using PostscriptPrinter printer. 
The postscript output is fine for english character but thai character 
is show as square. Could you tell me how to fix it?

Kan