I was at the apple store the other day with the same exact question (Only I have Ghost Armor on my iPhone 3G). I asked if I could try it on in the store to see if it fit. They made me buy it first to try it on. So, after trying to put it on in the mall for about 5 minutes, I found that it is too tight of a fit. The case does not snap onto the iphone comfortably with the Ghost armor. So I then went back to the store to return it.
Now, I'm assuming you mean the Invisible shield for both sides of the phone, back and front, because if you just want to use the screen protection from IS and the contour flick for the back protection then that would work fine.
It's too bad it doesn't fit though, because it seemed like it would be a nice case otherwise.