Austronesian languages exhibit features that are challenging for Universal Dependencies: most notably, the symmetric voice system, whereby agent, patient, and instrumental arguments (among others) can be the pivot of a transitive structure – complicating the usual assumption that subjects of transitive sentences are semantic agents, and objects semantic patients. To showcase our ideas of how to address the representation of such systems in Universal Dependencies, we introduce a small treebank of sentences from texts and elicitation sessions in Gorontalo, an Austronesian language of Sulawesi (Indonesia), which exhibits a Philippine-type voice system. We discuss the annotation guidelines for this language, and the extensions of the Universal Dependencies guidelines that are needed to accommodate this and other Austronesian languages.