ASUS Rampage II Gene Integrated Audio and Blu Ray

Hi,

I am building a gaming rig this weekend with an Intel i7-920, Asus Rampage II Gene, an overclocked GTX 295, and Corsair Dominator-GT 3x2GB DDR3 1866.

My question is in regards to the integrated audio on the MoBo (SupremeFX X-F): I will be using HDMI to connect this PC to an Onkyo Receiver (using my 54" flat screen as a monitor).

I will have a LG Blu-Ray combo drive as the primary. The MoBo says that it supports Blu Ray and I want to know if the integrated audio is sufficient for this? I also ordered a ASUS Xonar HDAV1.3 PCI card with True Blu Ray as I was not sure.

Can I (and should I) just use the integrated audio, or should I install the ASUS Xonar for it? If I install the ASUS Xonar, can I, or do I need to disable the onboard Supreme FX?

Any and all help would be appreciated. I haven't built a new gaming rig since Blu Ray has been out, so I am new to this portion, as well as having a gaming rig be a combo HTPC. Any suggestions for using a Onkyo TX-SR806/Panasonic TC-P54V10 Plasma as my display and sound are also welcome. As I said, I am new to connecting a gaming/multimedia PC in this way.

Thanks!