Manley Steelhead volume remotr control kit

[audiophile.1963]

Hi, I’m an owner of a Manley Steelhead II, the first serie without remote control. In the past I saw in Manley Labs site a kit for a remote control, but now it's gone. Could someone kindly tell me where I could find something similar? I want to keep mine.
Any useful advice is appreciated!
Thanks
Giuseppe