General directions

• Create a custom class in your description.ext.
• Set a value of some sort within the class.
• Try to fetch the value with getMissionConfigValue.

Specific example

• Add the attached description.ext to a mission.
• Go ingame and type the following in the debug console:

hint format["Value: %1", getMissionConfigValue "CfgAutodoor" >> "Vehicles" >> "Land_Airport_side_base_F" >> "doorList"];

• Observe as it displays something like this in the hint dialog:

Value: 02558CB8

The following excerpts from the BIKI is what makes this seem like incorrect behaviour:

• "Returns value of given scenario attribute from the 1st tier."
• "Return Value: Number, String or Array, depending on the attribute value type. Nil when the attribute is undefined."

Currently, in order to get the value you still have to fall back on the old getNumber/getText/getArray commands combined with getMissionConfig.

This is the aforementioned description.ext I've been used:
allowFunctionsLog = 1;

class CfgAutodoor {
class Vehicles {

		class Land_Airport_side_base_F {
			class Door_7 {
				class delays {
					stayOpen = 5;
					reopen = 0.5;
					closeReactivate = 0.1;
				};
				class disablerBIS {
					value = 1;
					varname = "bis_disabled_Door_7";
				};
				doorList[] = {
					"Door_7A_move",
					"Door_7B_move"
				};
				class sensor {
					radius = 4;
					triggerSelection = "Door_7_trigger";
				};
			};
			class Door_8: Door_7 {
				class disablerBIS: disablerBIS {
					varname = "bis_disabled_Door_8";
				};
				doorList[] = {
					"Door_8A_move",
					"Door_8B_move"
				};
				class sensor: sensor {
					triggerSelection = "Door_8_trigger";
				};
			};
		};
		class Land_Airport_right_F: Land_Airport_side_base_F {};
		class Land_Airport_left_F: Land_Airport_side_base_F {};

};
};