Hi there,
It shouldn't be too hard so here goes.
Download/Install Armin's IR Converter (Link can be found on the Wiki)
Open up the folder that contains the Cab (WAV) that you want to convert.
Select the correct WAV file and hit the open button.
You should see the IR wave form etc..
Now all you have to do is hit the Save As button and give it a name.
You should now have a cab file in the correct format.
To upload to the Axe you can either use the Lars Editor or the new fractal editor, I personally prefer the Lars Editor for which links can be found on this forum.
If using Lars Editor you should open up the Cabinet tab and click the select folder button.
Point it at the folder you saved the IR created above.
You should now see one or many IRs in the right hand window of the editor.
To upload the cab you simply drag the cab from the right window to the slot that you want in the left window.
This process will overwrite the existing cab in the slot you upload to so be careful.
The Red Wirez Cabs come in 48k 24bit which is the standard that the axe uses so you should be set to go.
Feel free to drop me a line if this does make sense