Outlook Web Access - notification sound when new mail arrives (IE8

Hello
I had IE7 and the OWA feature:
play notification sound when new mail arrives - works ok
show popup alert when new mail arrives - works ok

Now with IE8 i cannot hear the notification wav.
With IE8:
play notification sound when new mail arrives - not working
show popup alert when new mail arrives - works ok

I downgraded to IE7 and it worked again both features.

Then back to IE8, and got again the sound issue.

Any explanation/solution?
Any one with same problem?


Thanks