RDS8000 Mixing Help Needed

[rockNmayhem]

Hey guys like the title says I need help with my Airtronics RDS8000 radio setup. I'm trying to use it in my loader and I am wanting to get it to where I can use channel 3 & 4 for my cylinders which is no problem but I want to only have the pump running when I open the valves. Now both channels are separate and each function as they should no right now but I cannot seem to be able to figure out how to set up the mix to get the pump to kick on when I activate a servo. I was under the impression that I need a speed control on my motor for my pump but how do I run that through a separate channel to operate with channels 3 & 4?

If anyone can help me out here I'd greatly appreciate it. A little further insight to my setup is channel 1 & 2 are already set up through a sabertooth to run the tracks and that is working great. I only need to figure out how to wire up the pump at this point so when the servo's are in neutral the pump is off and when I increase the valves either direction the pump will turn on.

Thanks in advance for any help I can get.

Tyler