The question would also be, what you actually want to do with this value. If you actually need this value within your annotation processor, you might be out of luck, since class with the field itself is only created after the point in the compilation process where it is needed. If you need the value on runtime, you might have the same issue. But then you should consider changing your implementation, since handling annotations on runtime is very expensive.
Now coming to the point which might work. If you need the value to write it to sources you generate with the annotation processor, you could as well use this field as string value and write it to the newly created sources. You would only have to make sure to have the right imports set as well.
@SomeAnnotation("BR.someField")
When the generated code is compiled then, this field would behave exactly the same as if you would have put it in your self-written sources. Just make sure it does not end up in the definition of another annotation.
final int someField = BR.someField;