1IM 8.1.2: Column-Dependent configuration for Limited Value fields not working?

We have just migrated to V8.1.2 (from V7) and I now have to add a new functionality to the WebUI that requires the usage of a custom web component to edit a custom field in Person which uses a list of limited values.

For some reason, no matter what I enter in the Custom-Dependent config for that column, it still always uses the standard combo box element. (VI_Edit_LimitedValues). I've confirmed that using the debugger. 

So to see if there's anything wrong in our own setup, we used a clean installation and added the field "IdentityType" (which is an ootB LimitedValue field of Person) and added that to the "My profile" property list. Then we added a column-dependent config for Identity Type to refer to "VI_Edit_LimitedValues_RadioButtons". 

And again, that definition is ignored and we get the standard ComboBox. 

So it seems the column dependent config is simply ignored for LimitedValue fields. Am I missing something here?