Currently, the InstallWagonProviderTask hard-codes the 'WAGON_GROUP_ID' value internally with no way to override it. Because of this, it is impossible to use a custom wagon that does not have a groupId of 'org.apache.maven.wagon' to upload files with a deploy task. It would be better if the install-provider task used that value as a default (so that it would be specified in the common case), but had a groupId setter allowing it to overriden.