It actually comes down to more "the content on said USB" rather than just being USB.
Many TV can't digest DTS(that info is in the TV manual).
Your BD player will accept "basically everything".
The true test...is if the HTiB will accept DTS off the toslink. Many won't. But regardless...
Play everything in the BD player. If you run across DTS on a USB the HTiB won't play...go back into setup on the BD player and change it to doing the decoding.
Matter of fact...I'd set the BD player that anyway. The only issue will be if the HTiB doesn't accept multi-channel PCM over toslink.
You'll just have settings for audio to play around with.
Worst case is the HTiB won't take DTS or MCH PCM and you'll have to set DTS for "stereo downmix" and use Dolby ProLogic in the HTiB.