profile plot (x-axis)

[Angelina]

I want to draw a very simple network, which is composed of three pipes of different lengths, connected in series. I changed the lengths of each pipe and set the auto-length off, and drew the network (of course out of scale).

Now I want to graph a profile plot showing how the initial quality changes along the pipes. The graph that I get is correct but the x-axis shows the distance in meters as drawn in the map (i.e. out of scale), and not the real lengths of the pipe as defined in the pipes' properties. Does anyone know how I could fix that?

thank you!