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There is usually a "hold" function that allows you to strike a chord, then push a footswitch to "hold" that certain chord. While it is held, you can solo all over the place and the changes will be ignored. It only takes a little while to get used to. A bigger problem is the use of jazzy chords that involves "muted" notes on some strings. Certain arrangers read the muted notes as well as the open ones....another workaround.
The same rules apply to guitar/arrangers as do keyboard/arrangers...... you need to make certain allowances for compromise in your playing style so the arranger can do it's job. The use of the word "intelligent" in the arranger world is highly overrated - it really means: "Ultimate power" - the arranger is the boss, and don't forget it. We are the conductors,maybe but the machine is definatly driving the train. Learn the workarounds, and you will be free to be expressive and creative on another level. You can't expect to just "play the same" as you would in a truly live situation, and get the same results. Learn the quirks of the machine, and make it work for YOUR needs. Almost anything can be done with these new arrangers if you dig deep enough.
Also:
Check out if your arranger has a "guitar" controller mode - this will probably have the "hold" feature built in. I know of several Roland models that have done this in the past. For a midi guitar controller - it's a MUST HAVE feature.