I'm building up a bike and I'm at the point where I'm installing the cables and housing (by the way, I'm new to bike mechanics). One of the thing-a-ma-jiggers that the cable runs along just has a concave surface the housing is supposed to be attached to. I have two questions regarding this:

1. What do I use to attach the housing to this? Would I use a housing C-Clip, something like this: http://aebike.com/page.cfm?PageID=30...ls&sku=BR7841? I have a Bionchi that I noticed has the same thing-a-ma-jigger and it looks like there is some rubber clamp which secures the housing to it.

2. Why is this concave protrusion not just a housing guide that the housing can be threaded through? Is it because the housing is supposed to be secured at this point so that it doesn't move?

Thanks,
Nick