The screen in UC Surface is greyed out because your remote device (iOS device or Computer) does not have appropriate Device Permissions to allow it to control the mixer. This may be because they have not been set, or it may be because of a mismatch in mixer firmware and UC Surface version.
To see how to set Device Permissions on the mixer for UC Surface and Qmix-AI devices, see here:
http://support.presonus.com/entries/69089944-StudioLive-AI-with-UC-Surface-iOS-PC-Mac-Device-Permissions
UC Surface is only supported with StudioLive AI Consoles on firmware version 1.0.6452 or greater. Prior AI Console firmware versions are only supported with older versions of Universal Control AI (with the VSL-AI control panel on Mac and PC) or SL Remote AI (for iPad).
If you attempt to use UC Surface with an AI Console mixer on older firmware versions, the console will not recognize UC Surface, leaving you unable to set your device permissions until you've updated your mixer firmware.
It is always recommended that you use both the latest software and the latest firmware available for your product, unless some other condition prevents or complicates doing so.
If you need more information on updating StudioLive firmware, go to your My.PreSonus account and locate your mixer's Hardware Registration page (register your mixer if you have not done so). There, you will find Firmware versions for download as well as Release Notes for all software and firmware milestones.
For more information about permissions for StudioLive AI Console mixers with SL Remote AI and UC Surface applications, please refer to the following knowledge base links:
Permissions when using SL Remote AI (Firmware versions below 6452)
Permissions when using UC Surface (Firmware versions above 6452)