YEs, you can add the Shipping rate lookup server behavior to the confirm page manually, open the confirm page, then go to the server behaviors tab, click the plus button and select eCart -> Shipping -> UPS
you will also need to create the shipping rule, for the trigger us:
Based on UPS Shipping Quote Value > 0
for the calculation, use based on UPS Shipping Quote "plus" "0"
eCart uses the UPS Shipping quote lookup API.