I just found out that if I create a text box, and middle align the text + assign a background color directly to the textbox instead of creating a separate box shape behind it, that if I convert to outlines to send to press - the background color disappears and is omitted completely.
Now, that's a problem.
Why does it do this as the color counts as 'content'? What is the solution or workaround for that kind of work flow?
Why are you converting to outlines? Except for rare cases (like sending a file to a screen printer) this should not be necessary if you supply a properly created PDF files.
Asid from Steve's comment, the reason the color disappears is that when you create outlines by selecting the frame you are making a compund path and the text frame disappears, and the color fill along with it. Select the text, not the frame, and your color should still be there.
There are other things, though, that disappear when creating outlines, like autoamtic bullets and numbers and underlines. You should take a look at Possible bug: oulining text w/ flattener in CS5