Augmented Reality (AR) has been shown to enhance the data visualization and analysis process by supporting users in their immersive exploration of data in a real-world context. However, authoring such visualizations still heavily relies on traditional, stationary desktop setups, which inevitably separates users from the actual working space. To better support the authoring process in immersive environments, we propose the integration of spatially-aware mobile devices. Such devices also enable precise touch interaction for data configuration while lowering the entry barriers of novel immersive technologies. We therefore contribute an initial set of concepts within a scenario for authoring AR visualizations. We implemented an early prototype for configuring visualizations in-situ on the mobile device without programming and report our first impressions.