Cleaning the keyboard from the inside

Following the instructions on this page, I have dismantled my MBA, but the newer models have a black cover. Can anybody explain or post a solution on how to open that black cover??? How can we take it apart without ripping it? I spilled a glass of juice and I disassembled the MBA following the instructions, yet, this bit is not explained anywhere. All the solutions given by www.ifixit.com go as far as to this point. As of today, there is not a single solution (for an MBA mid 2011, either 11" or 13") that shows how to open this part. Not even in the MacBook Air 13" 2011 Teardown. Not even there. MacBook Air 13" Mid 2011 Teardown Any tips or pictures posted will help. Thank you!!!