Where to put Application level resources in a mixed WinForms + WPF application.

Question

At present we host a number of WPF controls in a WinForms application. I would like to create a number of global resources at the application level, where is the best place to do this?

If this were a straight WPF application I'd put them in them App.xaml but we never create a System.Windows.Application, the controls just go into the WinForms ElementHost and straight onto the Form.