8rda+ question on sound outputs

[bdunosk]

I purchased logitech z640 speakers to take advantage of the 5.1 output on the nforce2, specifically the Epox 8rda+. From a review on the internet, it appears that to use the z640's three prongs, I would not have the option of a aux-in. Is there any other included sound outputs, such as something that would occupy a pci slot, included with the 8rda+? I have a TV-tuner that requires the aux-in, and would be screwed if I wanted to use that and the 5.1 sound. Maybe I'll have to go w/ another brand?

Thanks!