DVD's dont play in 5.1

[Rokusho]

Currently I've got Creative G-500 speakers and a Creative X-Fi Music card

For some annoying reason I can't get dvd's to play in surround. However, HD trailers from Apple in Quicktime work fine in surrond.

Any help will be appreciated

 

[Rokusho]

I'm currently using inter actual player and if there is an option I havn't found it.

Of you have a suggestion for a better DVD player that you know will play in surrond sound plz tell me where i can get it