"You may or may not want this very basic hack I made to the change quantity function to bring in the current cart quantities for modification. Likely many others have hit upon it as well. It's in web_store_html_lib.pl."

if ($reason_to_display_cart =~ /change*quantity/i) 
      {
      print qq!
      <TD ALIGN = "center">
      <INPUT TYPE = "text" NAME = "$cart_row_number" VALUE="$quantity"
                       SIZE ="3"></TD>!;
      }