As I once retrofitted the whole Cruise Control to my 840Ci , I have ordered quasi all Items from this ETK page:
8er E31 Cruise Control
and I can confirm, you will not get the clip no matter the Item. Probably you have to search elsewhere... but I finally gave up
But ended with a solution with 2 zip ties
8er.org/forum/index.php?attachment/39553/
I hope you can see the two Ties... Just don't tighten the upper one (the clear in the pic) too much, so the cable can still slide a little bit.
Just went in the garage specially for you