5.1 through Displayport through HDMI through T240 through Klipsch GMX-D5.1

[Zepcom]

All, can anyone help me? I'm trying to get 5.1 on my system but am only getting 2.1.

Here is my setup: Alienware M15X (2010 build), which has only (a) a DisplayPort out; (b) two analog miniport headphones out; and (c) a microphone in miniport which Dell claims to support 5.1.

I have that connected to a Samsung T240HD, which has HDMI in, and Toslink Optical out.

I then have a Klipsch GMX D-5.1 5 speaker system. The controller for that beast has three inputs (only): Digital Coax, Toslink In, and two RCA inputs, which I assume aren't 5.1.

I have no idea how to work with the miniports on the laptop, so I've been focussing on a workaround with Displayport out -> HDMI adapter -> HDMI in on the T240HD -> optical out -> optical in on the DMX 5.1.

While this works to get sound to the Klipsch speakers, the computer (Windows 7) insists on outputting only 2.1. Any ideas on how to get the rest of the speakers to work? Any config, including adapters, welcome.

Oh, also, I tried also to use a Sound Blaster X-Fi Surround 5.1 external sound card (hooked into the laptop through USB, external out to speakers via Optical out), with the same results.

Help?