No Scroll Lock on Apple Keyboard
Having had a look at the StarTech SV215MICUSBA manual (PDF), on page 7 it says:


  To initialize Mac keyboard mapping, please execute the following
  hotkey  sequence:
  
  [scroll],[scroll], [F2], [Enter]
  or
  [ctrl] [ctrl] [F2] [Enter]
  
  Once this has been done, the following keyboard mapping will apply:


Then in the table below, it indicates that the Scroll Lock Lock key on a PC keyboard is mapped to F14 on a Mac keyboard. 

Assuming you have a full Apple keyboard, its probably worth trying this out.