Hardware (MAC) changed - no access to SUM

I upgraded my Hyper-V Host to 2012. As a result all virtual network cards changed their MAC address (I forgot to mark them as static before).
How do I access my SUM virtual machine now? The console just says "goto https://x.y.z.z:4444", but apperently SUM does not listen on that address anymore. Is there any way to edit the network configuration from the console?