volume control after sleep is for internal speakers

Hi, I'm using a Mac Pro with 10.6.2. I use external speakers connected to the line out on the back of the machine. In syst prefs, the selected output Line Out. Everytime my computer sleeps and I wake it up, the sound is still coming fro the external speakers but the volume control on th keyboard or menu bar will afect the internal speakers and not the external ones. Going to syst prefs, the Line Out is still selected. To gain control back to the external spekers I have to momentarily chose Iternal Speakers and switch back to Line Out. Any ideas on how to solve this? Thanks.

My Macbook Pro 3,1 uses a combined headphone/optical digital audio out port marked with a headphone symbol. It shows up in the audio output list as "headphones" when I plug my external speakers in. I don't have anything listed or labeled "Line Out." My audio output and volume controls switch back and forth OK. So, why don't you try running your external speakers off the headphone output jack instead of line out? See if that clears up the volume control issue.

That's exactly what I do. The line-out is the heaphone jack connection. In my MacBook it works just as you said to yours. Just plug in a jack and it switches automaticaly but this does not happen on my MacPro. I have to manually switch in Syst Prefs.