From my understanding of it, Inventor will not print the background colour at all and then prints the colours as they appear on the screen. Therefore white will not show up on a printout as white is usually interpreted by printers etc as "no ink here". If you view an IDW in VoloView for example that does not have a white background, on printing a view in full colour, the background colour is printed again. When we started using 5.3, the standard background colour was beige. We were using a workaround for printing (computers not connected to network at that time) and using voloview to print. On printing any views that were shaded, the background colour of the page would also be printed.
We now run using a custome setup where the background is white and the lines on the screen are black. There we many discussions about line colours in the old newsgroup.
Basically I don't think that trying to recreate an AutoCAD look on an IDW is the right way to go. Inventor is WYSIWYG in terms of the IDW environment.
Regards
Steve