Excel 2010 - Graph colour formatting

I am currently using Excel 2010 and I am using a bar chart to show my data. When I first create the chart, each line is a different colour (which is what I want) but when i select 'switch Row/Column' the bars change to different shades of the same colour. I have tried selecting different colour themes which doesnt work and I have tried changing each bar colour indivilually but when I then change the source data perimeters it changes straight back to the same colour. Anyone got any ideas to help me keep each bar a different colour?