How to set default audio output device for flash?

Hi there. I have two soundcards on my pc with suse 11.1, kde 4.2, both working ok,and wonder how can I make flash player use differnt sound card than it does now. I have set in yast default sound card device and it works in all applications ok (mplayer,amarok,vlc…) but for some reason when playing a flash movie in firefox 3.0.11 it uses the other sound card. Is there a way to change this? Thanks for your help in advance.