New RV. Solar/Inverter/Charger installation - Breaker Panel Wiring problems/questions

[bshellrude]

Hi all! New to the forums here, and have done some searching but have as yet found an answer to my question.

Here's the story. We recently had our old trailer written off by insurance, and so we bought a new 2018 359MBI. Love this thing, it's pretty swanky considering what we came from. Now, on my old trailer I had previously installed 3 160W Solar Panels, 6 Trojan Golf Cart 6v batteries, a PWM solar controller, and Xantrex 3500W peak Inverter/Charger. When the old rig was written off, I wanted to keep the system to install in the new rig. On the old one, because the Xantrex does passthrough as well as inverter/charger, the way I had hooked it up on the old one was to literally run it in line from the shore power to the breaker panel, while disconnecting/bypassing the converter/charger (as - at least they used to be - known for boiling batteries and just generally being bad at their job.)

So, I figured I could do the same thing with the new rig. i.e. run the Inverter/Charger in line with the shore power, disconnect the converter/charger, and all would be great! Well, I did get that all done... but I have now discovered an issue. Having not considered how the 50Amp 220 is wired into the panel (i.e. two separate poles in the box), but rather only that I would wire everything up "red-red, black-black, etc...", my problem now appears to be that because my shore power is running off 20A 120 right now (and thus only 1 of 2 120 lines is hot), I'm only getting one of the poles in the panel, and therefore only half of the branch circuits (only those that are on that pole).

Now that makes sense enough I suppose, with the exception of the fact that I'm 90% positive that all of the circuits worked when on 20A 120 before I changed the wiring. Which makes me think that there is some wizardry that I'm missing that Keystone has done inside of these things. I wondered for a moment if the converter breaker (which incidentally is live as it stands right now) was feeding the other pole, but only when 1 of the 2 hot wires was actually carrying power, meaning there must be some kind of ATS circuitry built in, but that seems improbable in my opinion. Then I wondered if perhaps the the converter itself was doing something funky/magical that I wouldn't expect, like controlling some sort of relay based on which pole it was receiving power from. This also seems improbable to me.

For all intents and purposes, if you consider that the Xantrex is passing the power through, the only thing that was done:
1) extending the length of the wire from the shore power plug on the rig
2) unplugging the converter from the back of the breaker panel (and I mean literally unplugging it from the NEMA 5-15R receptacle on the back of the WFCO breaker panel)

I have to admit I'm at a loss. like I said, for all I's and P's, it's wired exactly the same as it was when I started in. I have pictures to prove it!! lol... but even supposing that only one of the poles was working before when on 120v, all the things that worked before (i.e. fireplace, tvs, etc..) don't work any longer and using a MM there is no voltage on those breakers.

Everything I know tells me I must be missing some magical electronic switch/bridge/something. I'm hoping someone has run into this before and/or can explain to me how, with a 50A service, adapted to 120 single hot, one would normally power both poles of a 50A breaker panel.