Hello
If you boot the regular, non paravirtual kernel, you should be able to do a normal conversion w/o manual reconfig afterwards.
Converter always creates SCSI disks on the destination machine, this will happen also if the source is a physical machine or a VMware VM with IDE disks, but this has not caused any problems AFAIK. The /dev/xvda is a Xen virtual device and it is expected to be changed to /dev/sda.
I'd rather guess the issue is with the specific SCSI controller - probably the source has no driver for LSI Logic SAS, but perhaps is has for LSI Logic or BusLogic? Try changing the controller in the wizard and retry the conversion; better - verify which modules the source has beforehand.
HTH
Plamen