iscsi root: iscsi not started in initramfs

Ubuntu server daily disk; 20120908 (amd64)

I have a kvm guest which is diskless, I've done an install (off CD image) onto an iscsi disk (that's provided by another VM running tgt).
But it won't boot after install (maybe related to 881388?)
(Host is Quantal as of today but with 3.5.2-030502 to get around bug 1045027)

The install goes apparently fine; I tell it the IP of the target, pick the (only) target, and there's no auth.
I just pick openssh-server as the only item of task to install.

I boot, bring up iPXE's command prompt (with ctrl-b) and enter:
dhcp net0
sanboot iscsi:192.168.122.10:::1:iqn.2008-09.com.example:server1.share1

and it brings up grub and starts to boot and eventually lands at the initramfs prompt saying it can't find the root volume.

Using rescue mode I can see a lot of

ipconfig: no devices to configure
and
/scripts/local-top/iscsi: .: line 505: can't open '/run/net-*.conf'
(it's right there isn't any)
and *then* I see the messages about the networking coming up and finding a link.

If I manually ifconfig the interface and run /scripts/local-top/iscsi it brings it up and I can continue the boot and it boots OK.

This happens with the network interface configured as e1000 and hypervisor default (8139 something)

I'll attach the VM config from the host.

Dave