Clearing a skill function definition within scheme (skill++)

Greetings all,

I'm trying to figure out a clean way to un-bind a skill function within skill++.  The typical way is to simply assign the name of the function to 'unbound

e.g. _foo = 'unbound

However, if I have a function defined in skill and I try in skill++ to de-assign it directly, I get the error:

*Error* eval: can't update SKILL function in Scheme via assignment

One really kludgy way that I've found that works is to re-assign the function within skill++ to a dummy function and then unbind it.
e.g.

(defun _foo () t)
  _foo = 'unbound

This works however it has the side effect that it prints a warning in the CIW:

*WARNING* (define): redefining SKILL function _foo to be Scheme variable

Does anyone know of a better way to achive the same result?

Mark