Stratix V PCIe HIP not supporting Avalon MM Gen3 x8 I/F

Can anyone say why ?

I have a single EP design using Avalon MM interconnect and across Cyclone IV, Arria V and Stratix V and I want to support Gen3 X1, X4 and X8 on the Stratix V card ...

This is a problem to switch to Avalon ST interconnect for one design point ....

Any ideas on how to get around this ?

Thanks, Bob.