In DESCRIPTION.EXT using (If statements)

[=242= CPT. Helios 18]

I'd like to have a description.ext that changes a mission wide respawn template depending on different circumstances given. 

If the server is using ACE3, the respawn templates should be as follows

respawnTemplatesWest[] = {"Tickets","MenuPosition"};
respawnTemplatesEast[] = {"Tickets","MenuPosition"};
respawnTemplatesGuer[] = {"Tickets","MenuPosition"};

If the server is Vanilla, or otherwise not using ACE3, the respawn templates should be as follows. 

respawnTemplatesWest[] = {};
respawnTemplatesEast[]  = {};
respawnTemplatesGuer[] = {};

If I have to create an addon to this, that's fine, but I would rather simply keeping these constraints to the mission file. Here's what I've done so far

__EVAL(if (isClass(configFile >> "cfgPatches" >> "ace_main")) then {RespawnTemplatesWest = {};})

But this returns an Input after endoffile error, and I can't seem to get this to work. Is there a solution, or a workaround>
Would I have to create a new respawn template and somehow script this functionality in by hand?