Binding Keys

I'm trying to bind the keys ^j & ^k to scroll up/down lines in irssi.

These are my current keybindings:

Key                  Action
^j                   command sb goto +1
^J                   key return
Key                  Action
^k                   command sb goto -1
^K                   erase_to_end_of_line 

The problem is, the keybindings exist.

Now I've tried '/bind -delete {^k,^j}'.
Then rebinded the sb goto commands to them.

The original bindings can't be deleted it seems.

Anyone know as to why this is the case?
Can anyone telll me how I might be able to get these keybindings
working?

Is there an "order" I need to follow?

Would be much appreciated. Thanks.