ZedGraph - Fill between two lines

See more:

C#

Hi there.
I need to paint two lines(curves) and fill space between them(for example red color). This will be something like range of acceptable values for some test values. Maybe you have some generic sollution for this problem?
Drawing upper line with red fill and lower with white fill is wrong because when I put another range like this below it will not be visible because of upper white fill.