Invoice against Cancell billing document
user created move-out billing document & invoice for the period 25.12.2011 to 07.01.2011.
then user cancel the above billing document and invoice due to modification in billing document .
now again user created move-out billing document for the period 25.12.2011 to 02.01.2011.
when we are invoicing to that billing document two invoice are created one for the period of 25.12.2011 to 07.01.2011 ( for reversed billing order ) and second one for the period 25.12.2011 to 02.01.2011 ( for current billing order )