Use local DLL in designer - custom control

Question

I have developed a wrapper for Cards.dll enhanced and turned it into a custom control for a card game I'm working on.  The problem I'm having is that I can get the game to display the cards if I run the app, but I don't have any luck seeing the cards in the designer.  It's throwing an exception stating that it can't find the DLL in the designer view for my form.

Where would I need to place the DLL so that the designer can see it?

Thanks