I don't know how many honda civics this applies to, mine's a 2000, but...
I noticed a knockout in the center of the dash forward where it meets the glass. It's about 1.5 x 2.5 inches. Lifts right out. I was about to mount some velcro there to hold my Navibe gm720 when I noticed it. I popped it out and it's apparently an access to a large bolt fastening the middle of the dash. The little Navibe fit inside the space like it was made for it! I threaded the cable down through the passenger side, nestled the antenna into the slot, and popped the knockout back in. Very clean.