Wrapping an element in front of many other elements

I tried a couple of things (looked online and such), but ended up
getting more confused. I want insert <xxx> before the <afi> element.
There are many elements prior to the element closing. This sounds
simple, but newbie-ness is getting in the way.

before:
<afi><fault fcode="xx-xx-xxx"/><describe><fdesc>xxx</fdesc></describe></afi>

after:
<afi><xxx><fault
fcode="xx-xx-xxx"/><describe><fdesc>xxx</fdesc></describe><xxx></afi>

d