DataGridView and custom object

Hello.
I have an entity Customer with some properties like a name, surname and etc.
And in this entity I have object Currency(this is a class with 2 fields(Id and Value)).

I created an object data source for object Customer.
I set to datasource of my gridview list of Customer's.

dataGridView.DataSource = new List<Customer>{...}

Binding is worked nice, but column Currency is empty. I thought that in this column setted value of method ToString() of object Currency, but I was wrong.

How can I set value of column which binding on object Currency?