Hi Caroline,
RPKs can currently only be created with CityEngine 2013. Now, since that's not yet out, that's an impossible thing to do currently for 10.2 users. Additionally, the first hotfix will need to be run to eliminate some more issues.
Though also it's not yet final, when this hotfix will be released.
So it'll take some more time. Sorry for the bad news.
Send me a mail for more Esri-Distributor-specific info. 🙂
Ok ?
Matt