Set custom color in Interface Builder

Question

So I have this class MWColor with the following properties:

@interface MWColor : NSObject
+ (UIColor *)orange;
+ (UIColor *)green;

In the Interface Builder, for a given UIView, I currently set the background color manually, as such:

However, I want this color to adhere to the colors defined in my MWColor class.

Can I do this in Interface Builder, probably something like this:

Or should I do that in code?

I would prefer to do it in IB

Thanks for your insights!