I have the same ASR board as you, and a Corsair case (500R) with two USB 3.0 connections on the front panel. My front panel USB 3.0 connectors are working the same way as yours, one works and the other does not. I'm not sure if there is a problem with the USB 3.0 front panel connections on the case, but I'll need to explain this to you, and answer your questions.
Our board has two different chips that provide USB 3.0 support, the Intel Z77 and a ASMedia 1042. Each has there own driver, and their are only two USB 3.0 drivers on this boards download page, one for the Intel, the other for the ASMedia. If you check Programs and Features in Windows, you'll see each USB 3.0 driver listed.
Each of these chips provides two USB 3.0 ports on the rear I/O panel, for a total of four there, and according to the specs in the mother board manual, the Intel Z77 chip provides one USB 3.0 header for the front panel. So it's the Intel chip and driver that provides the front panel USB 3.0 header support.
Notice the specs say one USB 3.0 front panel header. Does that mean one USB 3.0 connection, or two? A front panel could have four USB 3.0 ports for example, would they all be supported? I'm thinking that the spec means only one USB 3.0 connection is supported, but I'm not certain.
I'm not certain because according to the specs of the Z77 chipset, it can support up to four USB 3.0 ports. We know two are used on the rear I/O panel. So the questions are:
Does the front panel USB 3.0 connection on this board only provide one connection on the front panel? Is ASRock not using all four that are possible according to the Intel spec? There are valid reasons why they might not be (they use a PCI-E 2.0 lane for each connection.)
Does the Corsair connector for the USB 3.0 front panel ports that connects to the mother board provide connections for two USB 3.0 ports? I think that it does, since if not that is a rather blatant hoax or lie (it connects to two port but only one works.)
Or, is the Corsair front panel I/O connector defective? Since you have two examples that work the same way, and mine works the same way, IMO that means it isn't defective.
I'll ask about this situation in Corsair's forum, but I'm not sure if we can get more information from ASR. Does this make sense?