Keyboard Line Output Problem

[sunny]

I have Yamaha PSR-3000 electronic keyboard,it has stereo fixed RCA line level outputs and also having variable AUX outputs(controlled by master volume control).My keyboard also have stereo AUX inputs for connecting other keyboards with the instrument.Now when I connect other keyboard(KORG PA-50) to AUX inputs of my keyboard i could hear the sound of the YAMAHA sounds as well as Korg PA-50 through variable AUX outputs of the YAMAHA keyboard and that's fine.
Now the problem is that i'm not getting the connected keyboard(korg PA-50) sound through line level ouputs of YAMAHA keyboard as i could hear only Yamaha sounds through line out and not Korg PA-50 sound, that means the AUX INPUTS are not routing through LINE LEVEL outputs as they are routing only through AUX outputs.
So how can i route the AUX inputs also to line level outputs?please help.

Thanks,
SUNNY.