Kickstart option to avoid "Storage Device Warning"

Hello,

My organization uses a script that calls virt-install providing a kickstart file to automate KVM virtual machine creation. This process needs to be automated as we create and destroy dozens of virtual machines on a nightly basis to test our applications. Our script works fine when installing older OS versions (RHEL 6.2 and prior).  But with recent OS versions (RHEL 6.3), Anaconda installation halts with a warning:

------------
Storage Device Warning

The storage device below may contain data.

Virtio Block Device
<device info>

We could not detect partitions or filesystems on this device.

This could be because the device is blank, unpartitioned or virtual.
...

[Yes, discard any data] [No, keep any data]
-----------

How can we avoid this warning, or accept it automatically?  I did not see an option in the recent kickstart documentation.

Here is the virt-install command we are using:

virt-install --name %{fqdn} --ram 1000 \
             --file /var/lib/libvirt/images/%{fqdn}.img \
             --file-size 30 \
             --location %{url} \
             --extra-args "%{boot-options} ks=%{url}/ks.cfg"\
             --noreboot

And here is the kickstart file:

install
network --hostname %{fqdn}
rootpw --iscrypted "%{crypt-password}"
lang en_US
clearpart --all --initlabel
part / --fstype ext4 --size 1 --grow --asprimary
part swap --recommended
part /boot --fstype ext2 --size 512 --asprimary
bootloader --location=mbr
timezone America/Vancouver
auth --enablemd5 --enableshadow --enablecache
selinux --enforcing
reboot

Thanks for your assistance,
Kay