Spring transactional package-private method

I have a Spring MVC app with all logic related to a single business concern within a single Java package (controller, service, repository, DTO and resource). I enforce this by making all methods across presentation, service and persistence layers package-private (no interfaces are used). NB: layer separation is enforced with Maven modules.

However, the repository shall also be @Transactional, and using Spring defaults (adding spring-tx Maven dependency + declaring @EnableTransactionManagement + creating a new DataSourceTransactionManager(dataSource) @Bean) isn't enough: the repository is no more proxified when it does not have at least one public method (I check this with AopUtils.isAopProxy() in an integration test).

What is the most straightforward way (minimal example) to solve this with Maven + annotation-based Spring + Tomcat? (I heard about AspectJ and would prefer to avoid it if another solution fits the need, because AspectJ seems complex to set up and is incompatible with Lombok --but I guess I could replace it with @AutoValue, custom aspects, Spring Roo, etc.)