I registered Cubasis successfully to Mysteinberg in iOS6. I've not yet upgraded to iOS7. AudioBus suggested not to update due to number of bugs in iOS 7. Better to wait for there next update.
i7 920 2.67Ghz. X58 Intel Mo.Board, 12GB DDR3 RAM, 512MB MSI PCIe 16x, Cubase 6.5.4, Halion Sonic, Halion Symphonic Orchestra, QL-Silk, Geist, M-Audio FW 410, PadKontrol, Nocturn, Triton.