Replacing a back deraileur cable in an old bike

[pippobaudo]

hello and sorry for my bad english,
I have an old bike (20 years or more i guess), it is an old road bike 27'' with a handlebar like the one for competition. (you know what i am talking about

I'd like to change the handlebar and make it like it is possible to change the gears on the back from the handlebar, like new bikes do (near the brake levers), the problem is that i have to find a support for the cable (see enclosed figure) to be put near the bike-body so that the cable can arrive to the handlebar. do you know where i can find these supports for cables and what is their name?

An other problem is that i have only 5 velocities and the new shifters are for 7 velocities ( is that possible to find shifters for 5 velocities?
Thanks a lot, this forum is great.

[DaveM]

You need a "clamp on cable stop" like this: http://bike.com/problem-solvers-2007-backstop-1-3-8-inch-two-cable-with-slots-cables-and-housing

I don't think you can get shifter like you want for 5 speed. The smallest will be 7 speed.
To put 7 speeds on your rear wheel you would probably need at least a longer axle if not a whole new wheel. You may also have to spread the frame slightly. Probably also need a chain and derailleur to match the shifter.