Spring AOP access both target and annotation values

Question

In my current setup, I need to access a method's annotation values AND the targeted class itself (or to be more precise, parts of it).

Here is what I am doing at the moment:

@Around("@annotation(CustomAnnotation) && target(myInterface)")
public Object interruptIfEmptyExtensionOrNoConnectorFound(
    ProceedingJoinPoint proceedingJoinPoint,
    MyInterface myInterface) throws Throwable {
        ...
}

The annotation carries an integer value designating a parameter (position) to do some checks on & MyInterface contains further (non-static) validation information.

If I add the Annotation to this method signature, I get

java.lang.IllegalArgumentException: error at ::0 formal unbound in pointcut 

once Spring tries to load the ApplicationContext. The same happens if I try to change parameter order in the advice and/or remove the "target()" entry from the pointcut. (This loading currently takes the form of a SpringJUnit4ClassRunner with having the aspect and the class implementing the Interface as beans in the application context file.

Of course, I can get the annotation's values with proceedingJoinPoint.getTarget().getClass().getDeclaredMethod(...).getAnnotations() and some for-each-ing, but using this way adds 10-15 lines to an otherwise 6-line-long parameter validation method and feels ... wrong.

I thought something like presented here would be possible if the "target" class is also in the advice method signature, but seems I am wrong or missunderstand something there.

Below are the non-working attempts to get the annotation:

 @Around("@annotation(CustomAnnotation) && target(myInterface)")
    public Object interruptIfEmptyExtensionOrNoConnectorFound(
        ProceedingJoinPoint proceedingJoinPoint,
        CustomAnnotation customAnnotation,
        MyInterface myInterface) throws Throwable {
            ...
    }

 @Around("@annotation(CustomAnnotation) && target(myInterface)")
        public Object interruptIfEmptyExtensionOrNoConnectorFound(
            ProceedingJoinPoint proceedingJoinPoint,
            MyInterface myInterface,
            CustomAnnotation customAnnotation,) throws Throwable {
                ...
        }

And this is how I currently retrieve the annotation:

MethodSignature methodSignature = (MethodSignature) proceedingJoinPoint.getSignature();
Method method = methodSignature.getMethod();
if (method.getDeclaringClass().isInterface()) {
    method = proceedingJoinPoint.getTarget().getClass().getDeclaredMethod(proceedingJoinPoint.getSignature().getName(), method.getParameterTypes());
}

CustomAnnotation customAnnotation = null;
for (Annotation annotation : method.getAnnotations()) {
    if (annotation.annotationType().equals(RequiresConnector.class)) {
        customAnnotation = (CustomAnnotation) annotation;
    }
}
return customAnnotation;