Optical device, sound question

MOBO - Asus A8N Premium, will be using "On Board sound", have CD-ROM and CD Burner installed (just finishing build), will be adding a DVD Combo drive in the future, would like sound from speakers plugged into Lime Green rear port, don't care about getting sound from the CD Burner, just CD-ROM and Combo drive (in the future) - will the 40 pin IDE connector do this for me OR do I have to connect the Audio cable to the "Black" MoBo connector ( CD ) and the "White" MoBo connector ( AUX ) for the future DVD drive ?? This is a little confusing -