Speedo problem with alloy wheels

I'm having a problem getting my speedo to work, it's a 72 bay with alloy wheels that don't allow the grease cap on, how do you hold the speedo cable in place without the grease cap ?

 

Im not sure you can

 

What wheels are they

 

they are 15 inch wheels off a passat

 

Can you bore the centres out, I did a set of granny wheels to the size of a beer can and used them as caps

 

The ones in this thread

http://thelatebay.com/index.php?threads/doka-daily.2589/

 

and you've the speedo working okay then ? I'm not sure if they can be bored out, I've to go see a mechanic mate who's a fabrication wiz on Tuesday so I'll ask him.

 

Yea worked OK it takes the grease cap