Your motd.txt file should be in <gmod root>, the folder that contains /addons, /lua, /materials, /models,
UTeam has no current way to control weapons load.
I believe the "somewhere" you talk about was by someone else who tinkers with lua code, and thought it would be possible to do.
(Technically, it is possible, however, we (Team Ulysses) have not written code into ULX, nor has spbogie (author of UTeam) written code to do it)