Would cruise control in a brick shaped heavy Pinz not be just holding your foot against the floor?
Jokes aside, can you post a photo of what the throttle linkage controls on the top of the fuel injection pump look like on your engine? The D24/T/IC engines use two different control systems depending on what vehicle they are installed in. VW LT applications use a simple throttle lever with a throttle cable running to the pedal. Meanwhile in Volvo car applications, the IP throttle lever is connected to a linkage rod that runs to a round spool that the throttle cable winds around, which provides a more gradual response to accelerator inputs. I am not sure which type of control system the Pinzgauer uses but it's probably one or the other depending who they chose to buy their parts from.
The reason this matters is that the Volvo style cruise control components are designed to work with the latter setup (round spools on top of the IP). The former setup, the simpler configuration seen on the VW LT applications doesn't have a factory cruise system available to my knowledge although if that's what you have, there would be aftermarket systems that could work fine.
Once we know what kind of setup you are starting with we can advise further on options.
