It's a bummer the fs9 textures don't display well in FSX.
I just googled for Joerg Zeitschel alias 'nemesiscom' -- on his current site he says that "...From 2003 until 2007 I was specialized in aircraft repaints and livery designs.
I have made more than 750 own aircraft livery designs so far - mostly for MS Flight Simulator."
At both AVSIM and Flightsim you can still get 66 of his textures. Flightsim is a better option for a look-see as AVSIM never managed to recover their older thumbnails following the attack.
Sadly, like so many other experienced re-painters he never made the move to FSX despite his extraordinary skills. It wouldn't surprise me though if he had teamed up with a few colleagues and produce quality payware for FSX these days like so many others in the general field of FS add-ons have done.
I would have suggested you try one of his fs9 textures just out of curiosity but of course he stopped texturing under his own name long before iFly released their 737.
Request: Should you accidentally at some stage stumble over a name or names associated with that
iFly 737 livery pack of yours, please let me know here or via PM - if you can remember