Am sorry for not having replied before. The submission was in May and have quite frankly forgotten about it.
"Please can you also clarify which kernel is in use in domain 0" The kernel in the host was the cited 2.6.32 xen kernel of that date. I have not responded diligently because back then I finally figured out despite my sincere testing at the time my submission was in fact invalid. After I finally found my silly basic error, the kernel did work effectively. Note. kernel = '/boot/vmlinuz-2.6.32-bpo.4-xen-amd64' ramdisk = '/boot/initrd.img-2.6.31-bpo.4-xen-amd64' It took the one single digit to undermine all my efforts. The initrd I entered did not exist. 2.6.31- was intended to be 2.6.32. It seems you missed it too. I copied and pasted the settings persistently. Apologies for absorbing your efforts when not required. Then, after so many months have moved on. When I last used the xen kernel in squeeze there was a flaw that I never submitted. When trying to boot a guest in hvm, the system was strangled to a snail's pace. I've not touched it in 6 months. With a new kernel and version of xen released, I'm sure it's old invalid news.