I'm sorry to hear that you're having trouble getting audio set up.
The first technician you spoke with was correct. The audio for DTS would have to be routed through the optical cable when using bitstream audiophile. This is listed as "Case 3" under the connections, on page 27 of the manual, listing DTS as a supported format for that connection scenario.
Our call centers aren't always aware of the capabilities of the many components, including receivers, that are available on the market. There are hundreds of new models every year. In some cases, receiver manufacturers - including the one you mentioned - offers firmware updates for their products too, and the Samsung phone support people can't speak for other products. It's difficult sight-unseen to diagnose every possible scenario when things don't work.
I do apologize, however, that you weren't able to get that answer consistently, and I'll be happy to pass your post up to the appropriate department for review. Our goal is to help, not irritate people.
I have recently bought a Samsung 46" C750 3D TV, Samsung BDC 6900 and the Onkyo HT-R538 AV.
TV and 3D is great, Onkyo is great and the BD player would be great apart from the problem where there is no DTS HD sound when using Bitstream Audiophile.
I know that a lot of other people have the same issue and it appears to be an incompatibility issue between Samsung and Onkyo. I'm on Onkyo's side here and think Samsung are just taking the p***.
Anyway, I contacted Samsung support this morning and explained the situation to a drone who struggled with English. His solution, use Fibre Optic! No I'm using HDMI 1.4.
I called again later and spoke to another drone, I explained that I was not the only person with this issue and that they must have a record of this issue being reported. All I wanted to know was if Samsung were working on the issue and when a fix would be available. The only thing she could say was I should take it back and exchange it! I explained that other people had already done this and that they still had the same issue and it was clearly a problem with the model. Same reply, "I think your unit is faulty".
By this time I was getting a little irritated so asked if there was a replacement unit for the C6900 that had the same features, "oh yes" was the reply, "I'll just get the details". After a while she then comes back to tell me that the C6900 is the only 3D player with those features!! I ask her if Samsung are looking at the root cause of the issue and working on a fix, "oh I dont know". Well what use are you then!?!?
What a waste of ******* time! These "support" people dont understand their products, clearly dont keep a meaningful db of reported issues to cross reference and clearly Samsung dont give a monkey's about these types of issues. I am a firm believer of good customer support, I'll stick with a company if they treat me as I would expect a customer to be treated. Samsung you are very very very very poor.
Will I buy Samsung again.....hmmmmmm prob not.