Neviter:
I can confirm that a combination of wifi and cable connections on the same network can work. At least on my system. After checking out a few other discussions, I found a lot of people that say it just works but a number of other people with mixed results.
Here's a pretty long one.
https://discussions.apple.com/thread/3374397?start=0&tstart=0
Some say it doesn't work. Then it does. Then it doesn't. After following some leads from this discussion, I found that my Mac Pro does not initially recognise my iPhone. However, if I shut the phone off, then turn it back on, it pops up on iTunes. This has consistently been the case after several reboots. I can confirm its address in the AirPort utility and even ping the phone, but it will not show up in iTunes after rebooting the computer unless I turn the phone off, then back on.
Hope this helps with your setup. I'm going to monitor the above discussion to see what develops. Good luck.