I don't think the issue you are seeing (buttons not responsive) is specific to iOS8 Beta. If I remember correctly, this was seen on iOS7 as well and has been fixed in the iOS HWC version 2.3.47376. It is important the application is regenerated using the Hybrid App Designer from version 2.3 SP04.
If you want to stay on version 2.3 SP03, please contact support for a patch on top of 2.3 SP03.
Thanks,
Andrew.