You can't (link to a sheet w/o opening the workbook)
You can either save the workbook w/ the chart as the active page,
or
Link to the workbook w/ the sheet as a bookmark
( <a href="workbookname.xls#worksheetname">The chart</a> )
Or just save the chart as an image or html page to import into your FP site
| How do I link to a specific Excel Worksheet (a chart) without linking the
| whole workbook?