Sony Stereo Question

Howdy,
I have an older Sony Mini Disc unit that I'd like to install in my Civic. I noticed 2 RCA connectors on the back of the unit called Bus Audio In, I tried to put a portable CD player on it just to see if I could pump sound through but it didn't work. (I planned to put an XBOX on it if it worked) Does anyone know what the jack is for, and how to use it? It has a separate special jack for the Sony CD Changers, which I have one of as well...
Thanks.
Oh yeah, and my glove box screws keep falling out, and the whole thing completely fell out today when I took the centre console out, and it dumped everything on the slushy floormats. How do I keep those things IN the holes? On a sad note, I noticed inside the glove box the specs for my car, including the max capacity, and since I'm broke and can't afford a new suspension, I had to break up with the girlfriend after reading that I should only put 395 Kg on the frame. Type in - 395 kilo in lbs - at google to see my ex...ps you can use google this way to convert anything....so cool

try locktite you can get it at any parts store or hardware store