DTS Surround options

[vig13]

I have a question regarding DTS surround with Blu-Ray discs.

Most of the Blu-Ray discs I've rented have DTS surround. But I have noticed that they are usually in DTS 7.1 surround.
I am using a PS3 as my Blu-Ray player, and I am connected with audio through optical cable to my Sony Receiver, which is a couple years old, but pushes DTS surround, and I only have a 6 speaker Bose surround sound hooked up.

So my question is this - if the Blu-Ray disc only offers 7.1 DTS surround, but I only have 6 speaker set up, will the audio at least still come through in 6.1 DTS surround, or am I limited to just dolby surround sound?

Normally when I choose DTS on non-Blu Ray discs, my receiver will show DTS either 6.1 or 5.1 on the LCD screen. But I have not noticed this when trying to accept the DTS 7.1 with Blu-Ray discs.

Does anyone have any answers?????