You pretty much need an experienced HR person to deal with this kind of thing - if your startup is, well, a startup, I am guessing they won't have anybody with

You pretty much need an experienced HR person to deal with this kind of thing - if your startup is, well, a startup, I am guessing they won't have anybody with the knowledge (or interest) to do the paperwork. I imagine there might be an exception if you were actively headhunted and the company wanted to hire a lawyer to deal with it.