Following some advice I read on various toad forums on the internet, I've decided to force-feed Onsokumaru.  He was very unhappy with this arrangement, but did swallow two waxworms.  Hopefully a few days of this will get his strength up and I won't need to do it anymore.  The picture here was taken after the feeding.  It is a 10 second exposure in very low light at ISO 1600.  You can see his eye fully dilated.