Typically, third-party video cards have had incompatibilities with A/UX. This goes back to A/UX 1.0. The manufacturers of the cards have had to release new ROMs to get their video cards (and therefore displays) to function properly with A/UX. SuperMac, RasterOps, and other manufacturers have done this.
Because there is no software workaround possibility, the burden of compatibility with the A/UX video drivers rests with the hardware manufacturer.
We will contact Moniterm's tech support and bring the issue up with them again. We suggest that the customer do the same if they want to use these monitors with A/UX 2.0. There may not be too much hope of a solution, if they are not even aware of A/UX. Furthermore, it would be unlikely that there would be a quick solution since ROM upgrades typically take a while.
The other route would be to try similar video cards and monitors from a third-party company that supports A/UX, and this may be the only solution depending on Moniterm's response.