Root port mode will be added in the 11.3 release. If you need root port mode of operation before 11.2, please open a case with Xilinx Technical Support and refer to this Answer Record.
http://www.xilinx.com/support/clearexpress/websupport.htm See
(Xilinx Answer 32742) for other Virtex-6 Integrated Block Wrapper v1.2 for PCI Express known issues and release notes.
Revision History 06/24/2009 - Initial Release