I found the list of items at work so here it is early. Search for the part numbers to make it easier:
Rick's Automotive -
www.motive-hardware.com
17-564 - 1 3/8" 90 deg tire valve ext
17-497B - 1 1/4" tire valve ext
McMaster-Carr -
www.mcmaster.com
91862A518 - 5/16-32 thin nut
I also bought some 90 deg exts from Hill Top RV when I was trying to find the right combination of parts. These didn't work but they had a different cap on them that worked better. I bought another set later for my second i180 but they came with a third cap style that didn't work. Here's the info anyway:
Hill Top RV -
www.hilltoprv.net
38241083 - 90 deg valve ext
One problem: There isn't enough thread to mount the thin nut and the cap on the last ext. The cap won't seat on it's seal. It isn't a big deal but I'm a stickler about that stuff. The cap on the 90 deg ext that I didn't use was shorter and worked perfectly. It was also flat so it helped keep the assembly flush with the tire. But like I said the second set I ordered didn't have the right cap. Maybe check a local tire store for one that works or file the cap shorter or leave it alone.
Good luck.