hahah this is for the integra, but i dunno if it is similar to ur or for those with aftermarket steering wheel. i'm just tryin to help since nobody respond to this thread.
#15 in the above 2nd diagram is the pad you are supposed to remove by using the 19 mm nut in order to remove the steering wheel.
here is the comment that i got from other board:
When removing #15 as shown in the diagram, by carefully putting a small flat blade screwdriver in the slot beside the piece to be removed. gently pry the center out of the center of the wheel. be careful not to cut the vinyl. after you get the center out, the 19mm nut will be about 2in within the open hole. Loosen the nut only about two turns. do not completely remove the nut. place your knees fimly against the bottom edge of the wheel, with steady pressure from your knees take yor hands and smack the bottom edge of the wheel. this might take a couple of times for the wheel to break loose. As I said do not take the nut off, until the wheel breaks loose . If you take the nut off and the wheel suddenly comes loose it can hit you in the face and might even break your nose. If it does'nt come loose you may need to get a wheel puller. The first methoed will save you money by not buying a tool.
i hope this help.