I have compared my files against other online tutorials as well as against A3 wiki: http://community.bistudio.com/wiki/Arma_3_Respawn
I have had previous success with setting up respawn in Arma and A2 and similar methods do not appear to be working in this version.
I have no enabled mods or add ons.
When I hit the ESC key during Editor preview (to test the mission), then select the Functions tab, I note that the respawnBase and respawnInstant functions are listed in the left hand index but when selected the white text area on the left is blank (unlike respawnGroup or respawnNone for example).