I was able to get something working by creating an initialization method on the interceptor. I don't really like it, because it ties me to the specific implementation of AuthorizationInterceptor, but it gets the job done (damn deadlines lol). I would still like to know if there is a better way to do this, so I am not going to mark my own answer in hopes that somebody comes along with a better way of doing this.
I modified the attribute as follows:
public override IInterceptor CreateInterceptor(IProxyRequest request) {
AuthorizationInterceptor attr = (AuthorizationInterceptor)request.Context.Kernel.Get<IAuthorizationInterceptor>();
attr.Init(AttributeParameters);
return attr;
}
And created an Init method on the the interceptor:
public void Init(params string[] parameters) {
AttributeParameters = parameters;
}