You've probably moved on successfully, but in case you're still working on this trace idea, here are some extra tips:
If you have a lot of stray objects, use the eraser on the bitmap (yes, it really works!) before you trace. Ideally, you would want to scan it in Photopaint, so it appears as you drew it, and make erasures there.
If you work only in PhotoPaint, then set up some extra layers. Select color ranges with the magic wand, switch to a blank layer, and then fill with the paint bucket or edit/fill. You can get some custom gradients and complex textures in this way.
Set your layer to "multiply" where you see the word "normal" -- these are blending modes, describing how the light interacts between layers. Multiply will keep the dark lines visible when you fill with a color.
Coloring on separate layers allows you to erase and change freely.
But tracing in Draw works too, and results in a cleaner image quickly.
In this design I scanned a bag and applied Trace Bitmap in CorelDraw.
http://www.cafepress.com/chasing_josiah.207577358 This next image needed cleanup after the scanner left some shadows, so I kept it in Paint.
http://www.cafepress.com/chasing_josiah/4594953