How do you use the summary tag?

[kevin javitz <kjavitz@fix.net>]

I am having trouble getting the total weight to display correctly.  I am
basing my catalog off of simple, and using their basket.html.  The
summary tag in the basket.html looks like this [summary
format="<B>Shipping weight:</B> %d" total=1].  This just displays a zero
on my basket, though I have a field with weights in my products.asc
file.  There does not appear to be any docs on the [summary] tag.  Can
someone please help me out, thanks