CSE Button style


how can I define an AUI styled ButtonExtension? I added ‘aui-button aui-button-primary’ to the ButtonExtension className attribute, but it only resulted a mixed style. Probably playing around with CSS could solve my problem, but I would expect, that we don’t lose the Atlassian stlye with the new CSE concept, moreover the default style of a ButtonExtension and LinkExtension are different. Could anyone help me?

Best regards,