export and printing qwt plot

[giusepped]

I just followed the examples in qwt disto.
Thr pinting is quite good.
However, when I try to export an svg file, I get also negative values inside the figures.

I mean: my plot data have negative values on the y axis, but when I plot, I fix the value of the axis to be positive. So on screen, I get only positive values.

The ps printing is ok. When I export the svg file, I get also the negative values, like in this figure.