ulx/cfg/server.ini
copy that file to your servers' cfg directory, then edit the following lines to whatever you wish them to be.
server.ini - lines 5-10
ulx addGimpSay "I'm a llama."
ulx addGimpSay "How do you fly?"
ulx addGimpSay "baaaaaaaaaah."
ulx addGimpSay "Llama power!"
ulx addGimpSay "Llamas are the coolest!"
ulx addGimpSay "What's that gun to move stuff?"