you can get a regular 1/4" to 1/4" speaker cable and again, take one end off and add a speakon connector to the two bare wires 1+ & 2+. The numbers are pretty tiny on the speakon connectors but once you open it you'll see the tiny numbers on there. Its' really pretty easy and obvious once you get your hands on the parts. I bought a speakon connector at local store and went home and did it. Or buy or take your speaker cable to store, buy the speakon end and see if they'll make it for you there.
I also own a speakon to 1/4" speaker cable but its a good brand and facory made so I did not want to mod that one. Maybe you can get one of those and just rewire the speakon end to +1/+2. Run the 1/4" side to your cab.
If you wanna try it yourself, you'll be surprised how easy it is. No soldering, just a small phillips head screwdriver, maybe wire cutters so you can cut one 1/4" end off. And to trim the tinned (soldered) ends off or cut the casing back to expose more of the wire ends. Once you get the parts in your hands, should make more sense. Let us know how you came out.