Help with photographing paintings

Having just posted my last painting, I had a nightmare of a time trying to get a decent photograph of it. I have a new camera which is really good, but even my husband's cameras (super douper all singing all dancing) can't overcome my problem. The issue is that because my paintings always have a lot of white paper showing, that white paper turns out in the photo to be blue or a dirty grey and to me it ruins the look of the work. I want to show the contrast between the white of the paper and the bright colours I use, but even trying to adjust things in Elements or on Picasa doesn't work. I know that in Photoshop that you can play around with the background and Roger has done this on occasion for me, but it distorts all the other colours in the painting and hasn't produced a usable image. Some paintings photograph better than others and it does depend on how much white paper is showing and what the other colours in the painting are. Scanning does improve things a bit for sure but with only an A4 scanner it isn't much use for the bigger paintings. I know you can scan in sections and then paste them together but that is beyond my ability on a computer I think. This is driving me crazy as I spent ages on a painting and then can't make a decent copy of it. Has anyone solved the problem or have a solution (bearing in mind that I have my limitations both with a camera and on a computer). I'll remember you in my will if anyone can come up with something!