AutoCad 2D :: How To Make White Areas Non-transparent Without Using Hatch Command

I've got a drawing in Acad 2010 which consist of about 6000 lines. The image is a ship, and I need the drawing to insert in a HMI screen.

Now my problem: The accomedation of the ship is white, as is the background of the sheet. I need the drawing with a black background, but want to keep the white color of the accomedation of the ship. When I change the backgroundcolor of the sheet to black, the white areas inside the drawing will also change into black. If I trie to hatch the white areas inside the drawing the program gives a messages that there are to many open bounderies.

I tried to make a blok of the drawing and move it on a black square, but then again the white areas will turn black.

So for short: How can I make the white areas non-transparent without using the hatch-command?????