Umm... Should not be too hard to achieve I would imagine. I've not used HKN in ages, but I would assume having your hotkey definition look something like below might do the trick. Perhaps someone else with more experience can validate:

Code:
<Hotkey ScrollLockOn A-Z, 0-9, Plus, Minus, F1-F12 except W, A, S, D,>
<SendLabel w1>
<Key %Trigger%> 
<Send Label w2>
<Key 1>
If I'm not mistaken, this would mean that while your hotkeys are active (ScrollLock is On), the window labeled w1 would receive the key that triggers the hotkey (ie: the one you pressed) and w2 would receive "1" every single time any of said hotkeys is pressed.