I can't answer the actual question, but I can relate that I fixed my Optima by replacing the fourth failed solenoid assembly with a series of parts. I used a hose from one of the assemblies that had been earlier replaced, connected it between the water line feed and a restriction valve (John Guest type fittings), connected the valve* to a re-purposed Grainger stainless steel 120 Vac solenoid valve that I had used for a different purpose some years earlier, and used the existing hose (with the Miele solenoid section cut off) to feed the dishwasher. The power line embedded in the existing hose was connected to the wires feeding the replacement solenoid.

Dishwasher pulling from under the counter was required because of where my water feed was located, but no dishwasher surgery was needed. So far this has lasted a couple of years.

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*before hooking up to the dishwasher, the restriction valve should be adjusted to supply the flow rate that the colored pre-filter of the Miele hose assembly is designed to limit the flow to. This is specified in the replacement hose kit, and in some Miele parts manual I downloaded sometime in the past. I vaguely recall my Optima being limited to 4 liters per minute.