Awning has been fixed. I ordered the MegaX57 tube and brace just as OldCoot recommended. I didn't take any pictures of the project but I'll try to describe the process.
First of all my order came within 4 business days. I live in SE Alabama and it was shipped from Tampa. Not bad.
The 3 foot section of tube was actually from an old Dometic awning tube that has been "recycled". Not a bad idea. My only problem is that they didn't file down all of the burrs and slag from the chop saw when they cut the section. That would be a nice customer service thing, but it's not totally necessary for me.
My brother helped me because it's defiantly a two man job if you've never done it before. We both watched the video on the Mega57 website and figured we could handle it. The scary part initially was the torsion spring. We simply didn't know how much load was on that thing until we pulled the tube off the awning arm. He held the vise grips and I removed the arm. Once we had it loose he realized that it wasn't going to rip his arm off while unwinding at 2000 MPH. We counted the turns and wrote them down.
Next we slid the awning off the tube. This was a feat in and of itself since the tube had broken in two and the two ends had become crushed at the break point. I laid the tube down on a 4x4 and used a hammer to pound it back into a somewhat round shape. I pounded out the sharp jagged points to avoid ripping the awning as it slid down the tube.
We cut out the bad pieces and filed our cuts and slid in the Mega57 brace to 2 1/2 feet on the left tube. Riveted it into place and then slid the 3 foot tube I'd bought. Riveted that into place leaving a 2 1/2 foot section to fit into the right tube. Slid the right side in and riveted that together. The one thing to make sure of is to keep the three channels properly lined up so your awning will slide on smoothly. We had to jimmy with it to make sure everything lined up properly. Now I had a 20 foot awning tube. Keep that measurement in mind.
Next task was to slide the awning back on. This was made difficult by the fact that when the tube broke in half, it cut the hard plastic rod that is sewn into the awning and runs the length of the tube inside the tracks. The fabric was ripped a little and wrinkled up. As we got to the first cut section of the splice, the fabric simply hung on any little protrusion or gap and wouldn't travel any further. I tugged, he pulled, we pushed, we pleaded and cussed. Nothing. We greased it up with WD-40 hoping it would slide past the pinch point. It was getting dark and we decided to tackle it the next day.
later that night my brother being the genius that he is, hit upon the idea to run a length of duct tape over the break point in the fabric and thus "reform" the hard plastic rod. The next day before my brother arrived I duct taped all of the tears and breaks in the fabric further eliminating any potential snag points. I was able to slide the rest of the awing on to the tube by myself. Hurray!!!! 90 % of the duct tape is hidden by the awning tube so I'm a happy camper.
Now I figured I don't need my brothers help any more so I called him and let him have the day off.
I wound up the two torsion springs and reattached the arms and proceeded to roll the awing up. Duh I rolled the left spring backwards and had to take arm off, unwind the spring, roll it back correctly and reattach the awing arm. Note to anybody who wants to do this. The right side spring is turned counter clockwise and the left spring is turned clockwise. Mine took 16 turns. Now the awning rolls up but the arms don't quite fold into the vertical rails that are attached to the side of the trailer. The tube is 20 feet just as I measured. I was sold a 20 foot awning on the trailer, however the tube isn't 20 feet. It's only 19 feet six inches. The other six inches is hardware. I wish I had known that when I made my first cuts.
Now I'm wishing my brother was here. I unrolled the awning, took the arms off again, unwound the spring on the left side, slid the awning off, drilled out the rivets on one side of the tube where I had made the splice, slid the tube apart, cut out 6 inches, and reassembled the whole thing again. By this time I'm getting really good at it. I did all of this in about 45 minutes the second time. The awning rolled up and fit snugly just as though it were fresh from the factory.
Long story short, this is a doable project. I was able to repair my awning and the MegaX57 does stiffen the awning tube just as promised.