Go download autohotkey, it's free.

Add a new script and paste this in it:

#Persistent
a::ScrollLock

Save and doubleclick it, if it's running there's a green icon in your tray area. This example remaps your a key to scrolllock.

Here's a list of the key names you can use. the letter and number keys are just spelled literally

http://www.autohotkey.com/docs/KeyList.htm

Thanks for that Ken. It looks confusing as... well.
 
Actually KeyTweak works after all. Silly me, I forgot to reboot!
 
 
Steve

  Thanks for that John. Fn+Pause/break works on my Logitech 350.