I think what he means by update by number key is that the values he is fetching are numbers, but they come back as strings. He wants to update the value that came back using the numeric keypad and store this updated entry.
When the 2D array of strings comes back you have to index the cell of interest using the array functions. Take this resulting string and feed it into one of the string to number conversion vi's (they are found under the string sub-palette of the functions palette). Then display the number in a numeric control. Once updated, you have to do the reverse, i.e. convertt back to string, put it in the correct place of the record to be written and update the record.
I hope this helps,
Jared