Changing from Mac G5 to Macpro PCI problem

Hello, I’ve been searching in the forum but didn’t found nothing that really helps me.
I have changed my old Mac G5 for a Macpro and I have a Uad audio1 and a Powercore firewire, both of then use PCIx slots.
Now the Macpro slots are for PCIe.
I wonder if any of you have been thought this problem and had found any adapter PCIx to PCIe or chassis or whatever than works.
I’m working with Nuendo 4
any help will be very welcome