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?.

TIA

Sebastian