geom_eli passphrase prompt unresponsive at boot after recompiling kernel without kbdmux

[Stars butts]

hai, I recently installed FreeBSD 6.2 onto a geli encrypted disk with the
/boot partition on a usb thumbdrive, after compiling the kernel without the
kbdmux driver.
however, my usb keyboard is completely unresponsive during bootup, and when
the prompt to enter my geli passphrase comes up I cannot enter it. I have
tried with several different keyboards and it worked on the previous
non-geli install. Any thoughts?