Originally Posted by oneclick

When putting the outer cable on a set of bars that used bar-end shifters I used a bit of hard plastic tubing under the wrap (cotton tape, shellaced).
This allows the outer to be removed if required and the tube stays put.
The tube was from the local hobby shop, it's what they use to package lengths of the music wire they sell (so was free, sort-of).
A bit of that and some sticky tape to hold it in place would do the same as the Shimano stuff.