QR printing a range of pages from a custom preview

I have my own custom preview dialog. I want to print a range of pages of a
report, so, I set:

QRPreview.QRPrinter.FirstPage := PrintDialog.FromPage;
QRPreview.QRPrinter.LastPage := PrintDialog.ToPage;

This doesn't works when I do QRPreview.QRPrinter.Print. QR always prints all
the report. There's a sample projects that shows how to print a range of
pages doing a complicated file truncation or something like that... What I
don't understand is why this two properties FromPage, and ToPage are there
if the properties doesn't works?. Is this another nice awful design mistake
of QR or I'm missing something?.