PCI Passthrough not working on XS 7

I have installed a Xenserver 7 via UEFI in a Xeon E3-1230 v5 with a mobo Intel S1200SP-L. Almost everything works fine, excep for the PCI passtrough, i've followed the instructions in http://xenserver.org/discuss-virtualization/virtualization-blog/entry/pci-pass-through-on-xenserver-7-0.html but had no luck, VT-d is activated on the BIOS.

On my first attempt i wanted to use a NIC on a Centos guest (HVM), it seems to "work", actually the device appears on the 'xl pci-assignable-list', and the VM sees it with the correct driver (at least looks like that), but it doesn't work at all.

My second attemp was an USB PCI device on a Windows Guest, and the behavior is the same, the VM sees the device, but cannot initialize it (according to the Windows message).

Am i missing something?, i've been having a really hard time with Xenserver on this Hardware.