Really depends on the antenna your using... As you said, standard they have a separate control module in the VR which provides the triger signal to go up or down.
The only aftermarket one I have installed did not have this unit it was a 4 wire setup 1 to earth (goes to base of mast), 1 supply (to battery via fuse) & 2 trigger wires for up or down, requiring a momentary supply of positive current to one these. If you can still buy an aftermarket one like this then it would be very easy to hook it to the switches via the 2 trigger wires. Not sure about wiring a standard one though, as I think they require the module?