Where does one report bugs in backports?

initramfs-tools 0.77b\~bpo.1 arrived in sarge-backports recently. It appears to Depend: on klibc-utils (>= 1.4.19-2), but should probably depend on klibc-utils (>= 1.4.19-2\~bpo.1) instead, since it's otherwise uninstallable on a sarge/sarge-backports system.

Who should i report this problem to? it seems like filing it as a regular debian bug would amount to clutter on the BTS, but i can't find a comparable system for bpo.

i just asked on #debian-backports, but i've gotten no response there in my (admittedly short) attention span. the Maintainers: field is just the kernel team, who i doubt deserves to be nagged about sarge-backports, busy as they are.