I have 6i, not 8, so I don't know if the "Read from Spreadsheet" vi was updated to take multiple data types or not.
But with 6i, one way to do it would be to read in the entire spreadsheet as a series of strings and then covert the numerical data to numbers via the conversion functions.
Open "Read from spreadsheet" vi via the "edit library" command, or add "read from spreadsheet" to a vi and double click on the icon to open it with LabView. Save as (not in the library) "Read from spreadsheet (as string)" and follow the directions in the vi on how to convert it to read numbers to reading strings by replacing the pertinent pieces with string controls/indicators on the panel.