I have bought a couple suits @ Jos A Bank in Mishawaka (Univ Park Mall).
When I tried on the pants & jacket I just told the tailor, "Hey, you're going to see my handgun; I'm licensed & carrying legally" or something like that.
He was fine with that, asked me if I work security or something. I just said no, I carry for my own protection.
If you're cool about carrying, they'll be cool about it most of the time.