So Sorry to hear about your 'Opppsie' .
Don't feel bad.... you won't do it again
There hasn't been a year go by that I have not seen a RV sewer hose dead on the side of the Local highway.
An easy fix , if you still plan to use the same storage location, is to purchase Two 1/4" thick hex head stainless steel bolts 1/2" longer than the storage box bumper.
Also buy 2 Stainless split rings... that will be placed in the 1/8" holes you drill in the bottom end of the SS bolts.
Drill a 1/4"+ hole through the bumper box and the
end caps installed (at the same time) very near the ends...right through and out the bottom.
Note: You should mark (the inside) of the end caps to be sure they go back on in the same drilled position....denote 'up' for example.
Slide the bolts down through the 1/4" holes and place the slip rings through a 1/8" drilled hole that you have to drill at the bottom end of the bolts....this will keep the caps in place.
Hope this helps
'07 WildCat 30 RLBS ~ West Coast Edition ~
Trail Air - Tri Glide Pin Box
2000 F350 DRW 7.3 Diesel Lariat 89k miles
Edge programmer, 4" SS exhaust turbo/back
Vancouver Island, B.C., Canada