[Users] Change virtual disk interface

I have serveral "old" KVM virtual images, all off them using virtio for networking and disks. Trying to import these into my EXPORT datastore ends up with an error: virt-v2v -i libvirt -o rhev -os 10.0.0.3:/nfs/export  -n br0 PXE5-test PXE5.img: 100% [=====================================================] virt-v2v: WARNING: Unable to convert this guest operating system. Its storage will be transfered and a domain created for it, but it may not operate correctly without manual reconfiguration. The domain will present all storage devices as ide, all network interfaces as rtl8139 and the host as x86_64. virt-v2v: PXE5-test configured without virtio drivers. How can I avoid these errors? How can I fix this error. After restoring the image, I am able to change the network interface from rtl8139 to Virtio. However; I cannot change the disk. In the admin console going to Virtual Machines --> <virtual machine> --> Virtual Disks --> <disk> --> Edit gives a menu, but the only option I can change is "is bootable". Options  like "Interface" are grey and cannot be modified.