I'm having this same issue. I have an EVGA 240mm CLC and I've enabled both Corsair Link sensor support and Asetek LC sensor support as I believe was recommended elsewhere. Under Computer Summary, I see the USB device CCIV which I believe is associated with the CLC.
Even with these settings, I've been unable to locate sensor data in AIDA64 for the CLC fans while this data does appear in the EVGA Flow Control application.
Running AIDA64 Extreme version 6.00.5100 and EVGA Flow Control version 2.0.7