It is somewhat strange that you are observing this erroneous behavrior. I tried to reproduce the problem in VS2008 and with version of our controls that you were using, but I could not. After changing the Rotation property of any of the axes or the ChartSeries and clicking the OK button or the Apply button the designer was immediately updated. The .aspx file was updated accordingly and when browsing the page the chart was displayed as expected.
I recorded a video to demonstrate. You can find it here
the Telerik team
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