I am trying to work out how to populate `Foo` from `FooConfig`:

```
class Bar
{
   int A;
   int B;
}

class Foo
{
   Bar BarValues;
   Bar BarErrorValues;
}

class FooConfig
{
   int A;
   int B;
   int AError;
   int BError;
}

```

`FooConfig` is essentially a flattened version of `Foo`.

I can populate the `BarValues` easily with AutoMapper (by having a map defined for `FooConfig` to `Bar`), but I am having trouble getting the `BarErrorValues` populated - everything I try it ends up with the `A` and `B` values in it instead of the `AError` and `BError` values.

I suspect I need to use a "transformer" or `RecognizePostfixes` (although this does not seem to work as I tried it).