In informal community-driven knowledge collections like wikis, there is no well-defined way of reporting issues with knowledge items. When something is wrong or needs improvement, there is hardly any support for the community to communicate this in a focused way. The workflow of discussing about an issue, coming up with ideas on how to solve it, agreeing on the best idea, and finally putting this idea into practice in a retraceable way is sometimes standardised in terms of best practices and social conventions, but not supported by of knowledge management. We present an approach to improving this in a semantic wiki, where not only the articles contain structured knowledge, but also the discussions about this knowledge are structured using an argumentation ontology. We show how, by domain-specific extensions of this ontology, the wiki system can not only support a focused discussion about issues but also assist with putting solutions approved by the community into practice in many common cases. This is demonstrated on the prototype of a system in a use case from mathematical knowledge management.