Designer files preservation

Question

Hi, 
c#, Winform, VS2008, WinXP, .NET3.5

I build a chart in my main form using the VS charting wizard. 
As some properties are missing in the wizard, I add/modify them manually in the form designer.
Example: Grid-lines, axes min and max, etc.
While the chart looks OK, the manual modifications to the designer are not preserved, and every time the file is updated, the added/modified lines are removed, and the chart goes back to its original wizard generated chart.
Is there a way to make the manually designer modifications permanent?
(I could probably make all changes and modifications in my main, but I prefer to have all basic properties in the designer).