code: public boolean removeMap(String attribute, String key) {
  	NameOpValue nv = rslTree.getParam(attribute);
  	if (nv == null || nv.getOperator() != NameOpValue.EQ) return false;
  	List values = nv.getValues();
  	Iterator iter = values.iterator();
  	Object obj;
  	int i=0;
  	int found = -1;
  	while( iter.hasNext() ) {
  	    obj = iter.next();
  	    if (obj instanceof List) {
  		List vr = (List)obj;
  		if (vr.size() > 0) {
  		    Object var = vr.get(0);
  		    if (var instanceof Value &&
  			((Value)var).getValue().equals(key)) {
  			found = i;
  			break;
  		    }
  		}
  	    }
  	    i++;
  	}
  	if (found != -1) {
  	    values.remove(found);
  	    return true;
  	} else {
  	    return false;
  	}
      }
docs: Removes a specific key from a list of values of the specified
  attribute. The attribute values must be in the right form. See
  the 'environment' rsl attribute.
  
  @param attribute the attribute to remove the key from.
  @param key the key to remove.
  @return true if the key was successfully removed. Otherwise,
  returns false.