Install on a XEN DomU from within running Linux system, with pvgrub2, without MBR

[zirias@]

I'm using a virtual server from a provider who offers several Linux installs (among others Debian, which is something I could live with ...), but nothing else, unfortunately. Of course, I'd prefer running FreeBSD on that virtual server as well. I doubt there's a chance, but maybe someone here has an idea.

• I have no console access.
• The host seems to use XEN, with "paravirtualized" guests
• I'm only given two partitions (/dev/xvda1 for the FS and /dev/xvda2 for swap), no entire virtual disk (no /dev/xvda available), so, no MBR either
• Booting seems to use PvGrub2, as there's a /boot directory with Linux kernels, matching initramfs images and a grub2 configuration

So I guess there would be (at least) two problems to solve:

• Somehow chainload a FreeBSD bootloader (with a "fake" Linux kernel or something like that?)
• Use an offset into the existing PV partition for a FreeBSD root filesystem

Well, so, any ideas? Or am I really out of luck here?