German Semantic Role Labeling is suffering from sparse data. In particular, only a small corpus for VerbNet-style SRL for German is available: the Semantic Role Triple Corpus for German (SR3de). This corpus contains parallel data with VerbNet, FrameNet and ProbBank annotations. We extend the VerbNet-annotations using data from the other SRL frameworks, and show that a simple Multi-Task Learning architecture with similar auxiliary tasks (peer task) can improve the quality of the automatic SRL.