Decks, Patios, Porches and Docks - Adding an arbor - can't dig post holes

My aunt has asked me to build her an arbor over part of her existing wood deck. The arbor will be 7 feet high, and about 9 feet wide and 9 feet long. The arbor (like a trellis) will only need to support some ivy branches. The problem is this: I can't cut through the deck's floor and dig to sink a 4x4 because there is roughly poured concrete underneath. (Looks like someone just emptied the extra concrete in a big pile.)

Is there a surface-mount receiver for 4x4's, or something like that I could use instead? (The four corner posts will be 4x4's - the rest will be 2x4's.)
I'll try to include a link to a photo of what I'm hoping to build.

http://www.cloughconstruction.com/images/12A_freestanding_shade_arbor700.jpg

Thanks a lot,
Sampson in Wisconsin

If the arbor is freestanding, the posts HAVE to be embedded in a concrete footing. This is what gives you the lateral (side to side) support to keep it upright in a wind storm. If you embed wood in concrete, you'll be replacing it in about 15 years, maybe sooner. Steel posts or aluminum posts -- wrap them with wood if you don't want to look at the metal.