I do too, and they most certainly do work. They are my primary go-to for certain sounds.
Here's how I do it:
1. Launch Axe-Edit, and make sure it's connected (status bar at the top will indicate such)
2. Launch Axe-Manage
3. Under COMPUTER in the left pane of Axe-Manage, navigate to the folder on your computer where the Axe-Fx II specific IR's are located.
4. In the right pane of Axe-Manage, right-click on the IR you are interested in loading, then hover your mouse over the "Send To..." menu item.
5. Once the sub-menu opens showing all 50 user slots, move the mouse until you are hovering over the slot you are interested in loading the IR into, and click the mouse. Axe-Manage should automatically upload the IR into that slot.
If you are getting an error, make sure the .syx files you are using are the correct ones. The file size should be 10.6 KB in the list pane when you go to select them.
Best luck.