At the moment, the current version of the module does not support k2 component, i made a request for our developers to do this, may be it will available in next version.
You can clone your K2 articles to joomla category and use the settings used in the demo site. That will help you get around the issue until we release new version.
Since, slidehsow II module is used in over 30 of our templates, any changes to its core, would require through testing of all the templates. We have already released other extensions which now support K2 and joomla both. Over the time, all the extensions would be covered to provide K2 support.