AttributeDrawer: Draw parent property? (the one [AttributeName] is attached to)

The presets property has a custom attribute attached to it and is an array of a custom serializable class. in an attribute drawer class, the property and position passed in the OnGUI() parameters are for each child inside presets. I'm trying to attach the "+" button to the bottom of the presets property though to allow the extra space it needs.

right now, I'm attaching it to the last property. If I try to override the GetPropertyHeight() with extra space, it applies to all of these properties and that's not what I want.

I'm also currently getting the "presets" property with

 properties = property.serializedObject.FindProperty(property.propertyPath.Remove(
              property.propertyPath.Length - (".Array.data[".Length + 2)));

and I tried to set the height like this:

 Rect mainRect = properties.rectValue;
 mainRect.height += 20;
 EditorGUI.PropertyField(properties.rectValue, properties);

but I get

InvalidOperationException: The operation is not possible when moved past all properties (Next returned false)

I really would prefer not to write a custom editor script for the Example class.

http://answers.unity3d.com/questions/1364895/custom-property-drawer-overlaps-with-other-compone.html

I also checked this out, but they're trying to fix spacing within the properties themselves, not the parent property.