problems exporing spreadsheet to JPEG

Hi,
I'd like to export an spreadsheet to JPEG.
Unfortunately only 7 of 17 columns are contained int the jpeg file.
Is it possible to remove the padding? The jpeg should only contain the
table without space at it s borders?
The function for exporting the spreadsheet looks like this:

void
export2jpeg( Reference< XMultiServiceFactory > const& xMainComponent,
                     std::string const& documentFile) {
    Reference< XStorable > xStore{ xMainComponent, UNO_QUERY };
    Sequence< PropertyValue > storeProps{ 1 };
    storeProps[0].Name = OUString::createFromAscii("FilterName");
    storeProps[0].Name = "FilterName";
    storeProps[0].Value <<= OUString::createFromAscii("JPEG - Joint
Photographic Experts Group");
    xStore->storeToURL( OUString::createFromAscii( documentFile.c_str() ),
storeProps);
}

Thank you in advance.
Oliver