corus is right, salary information is as private as you want it to be. I have been asked in the past as to what my salary was. I was always polite and asked them how that relates to the conversation at hand. What I mean by that is, all the moves I have made have not been lateral, so past salary history is irrelevant. I go in armed with what the position I am seeking is worth and bring that to the front of the conversation when asked about past salary history.
Now you may ask how you find out what the position is worth and that is where you have to do your homework to be prepared. If you do not know, then the company will win. You have to treat salary negotiation as a game, where the is a winner and a loser. You do not want to be the loser. And if the company wins, just who is the winner, an HR person that gets a good review because they shortchanged you into the company? I have found companies to be very willing to accept numbers that represent the position once they realized that I knew the worth of the position. I have had several interviews where salary never came up in the first interview, it was implied through my manipulation of the conversation that I understood the worth of the position. This puts the interview into a stage where you can sell the employer you value.
I never gave anyone my pay stub. If it comes down to that being the deciding factor, you have to ask yourself as an engineer...do you really want to work there?
Let us know how you make out....
BobPE