When Userpoints is only payment type, don't require billing address/info

Noobish question: If userpoints is the only payment mechanism, and I have a captive audience of known site members authenticated by Active Directory, I don't need to collect billing info.

I put

#billing-pane {
display:none;
}

into the ubercart/uc_order/uc_order.css

which hides the billing pane, but then I get an error on the next screen that the fields are required.

Thanks in advance.