Because I dont have any copy of ISO image so I must download it from Cisco. But I cant find any ISO file for virtual Appliance in download page ( only OVA type).
You should be able to mount the physical appliance ISO (NCS-APL-1.3.0.20-2-K9.iso) when booting your VM. You'll need to shutdown and modify the VM BIOS settings in Vcenter to do this.