Well, looking at a dump of the buttond command with the command:
I find the following text:
Usage: %s resmgr_pid resmgr_child
as well as:
Error Generating the button %s
Perhaps %s is the scancode generated for a particular key you want to remap, let's arbitrarily call it "XX".
So perhaps this will work:
Use resmgr to execute a new button task, ie. pterm. Use "psin" or "ps -a" to find the pid for resmgr (ie. 123) and the pid (22222) for the task you want to execute with %s. Then, if you execute the command:
buttond XX 123 22222
Does this remap XX to the new task? Someone try this and see if this works. I'll try to give it a go later.