Working with ranges and UDFs

Hi all,

I apologise for the newbie question. I use a very simple VBA UDF that
I wrote to compound financial return stream presented as percents.
Essentially, it takes a range, adds 1 to each entry, multiples entries
from top to bottom (although the order is irrelevant), subtracts 1,
and spits out the result as a percent. This can also be accomplished,
to sufficient accuracy, using the line entry {=GEOMEAN(1+range)^(COUNT
(range))-1}. How can I make AppleScript to the same thing?

Cheers,
Alex