of course i don't know the specifics of your frame (which frame is it?), but generally speaking the tubes are hollow and the cable stops have been pressed or bonded in. since that segment you mentioned is designed for inner cables only, i'd bet a good amount of money the tube is just straight-up hollow.

the cable stops would not be structural, then.

if it were me, i'd take a very small drill bit and enlarge the existing hole, then increase the size by 1mm or so (or the imperial equivalent--maybe 3/16") until i reached the smallest size that will allow the e-tube wire.

it's probably a plastic stop. high speed with even pressure should do the trick. a dremel with appropriate bit will work, too.

if you don't own the tools it could be a good way/easy project to justify buying the tools rather than paying someone.

don't forget a small rubber grommet to seal that exit from the frame.

in the time it took me to type this one could have completed it; it's pretty easy.