The best option would be to not use
a DetailsPresenter at all. After all the DetailsPresenter is a simple empty rectangle which you
fill with UI based on the RowDetailsTemplate. You can easily do this without using the Row Details feature at all, since your details will be outside of RadGridView.
Simply take everything that you have defined inside the RowDetailsTemplate and create an user control out of it. Then set the DataContext of this user control to be the CurrentItem of RadGridView with ElementName Binding. When the user moves around the current item in the grid, because of the Binding the DataContext of your user control will change to be the respective data item (i.e. business object). Since the UI elements inside your user control will be data-bound to the properties of your business object, when the CurrentItem of the grid changes (i.e. this is the business object) your UI elements inside the control will update accrodingly.
This is a general WPF Binding technique. More about WPF Data Binding you can learn here
I hope this helps.
the Telerik team