I'm not the best scripter around but this should work:
// Call: nul = this addAction ["Mark-Location"[color=Red],"UnitLocs.sqf",[/color]["pMarker",player,1,1]];
_mName = ((_this select 3)select 0);
_pos = getPos((_this select 3)select 1);
_x = ((_this select 3)select 2);
_y = ((_this select 3)select 3);
_mName = createMarker [_mName, position _pos];
_mName setMarkerShape "ICON";
_mName setMarkerType "DOT";
_mName setMarkerColor "ColorBlue";
_mName setMarkerSize [_x, _y];
exit;
If anybody knows better please point it out, I'm just a beginner ;)