Google Checkout XML API - Float Quantity?

Question

I'm trying to send cart information to Google Checkout using the XML API. My products are sold by tons and partial tons, so sometimes the quantity is 1.5, for example. It appears the API only accepts integers for quantities: http://code.google.com/apis/checkout/developer/Google_Checkout_XML_API_Tag_Reference.html#tag_quantity

Is there any way around this? I'd like to send quantities with decimals (aka a float, not an integer).