How would I use my rank in an email signature block?

Retirees maintain their retired rank as an honorary title. When using that title they must identify themselves as retired. When a retiree works as either a federal government employee or contractor they may only use their honorary title in official correspondence if the the correspondence pertains to the retired status. For example if I am corresponding with the MTF concerning an appointment I can I identify myself at MSG(R) Eckert since the appointment is predicated on my retirement. If I am replying to an email concerning Army Doctrine that was sent to me as an Army Civilian, I cannot use the MSG(R) designation since the correspondence does not pertain to my retirement. Adding an edit, while you do not have your rank as an honorary title, there is nothing to keep you from identifying as a veteran in you signature block.

Let me clarify. I am not looking to stroke my own ego. The company I work for does a lot for veterans and wounded soldiers. My boss mentioned putting it in my work email signature block. If this is not something normally done then I will not do it. I apologize if anyone was offended by my question. Thank you for all of your responses.

I would let this one go. I've been retired from the Army for over six years, and have been working for a private company in a federal building. No one cares to tell the truth. Most of us go by first name basis even through emails. The only time I brought up the fact that I was retired and a veteran was when I first applied to the job I currently hold. Civilian world is so different, it is what it is.