Eric -
Webasto Company, a German company, is located in Stockdorf, Bayern, Germany, and has a USA office located in Michigan. Aqua-hot Corporation, a USA company, is located in Longmont, CO. After a little research, it appears they are nearly separate heating devices - the Webasto versus Aqua-hot, and it appears the companies are not related. Although... I know the Aqua-hot control device, a small rectangular box, is called a Webasto and is likely originated from the Webasto Company in Germany.
Our coach has the AHE-100-02S Aqua-hot and it does have a common coolant loop going from the coach engine through the Aqua-hot and forward to the dash heat. Our coach can be heated by the Aqua-hot diesel burner and/or the Aqua-hot 120v electrical heating element and/or heat from the running coach engine. I presume engine coolant is pushed through that loop by the coach engine's water pump. In addition, the Aqua-hot has an engine pre-heat function with a water pump in the Aqua-hot for pushing heated coolant between the Aqua-hot, engine, and dash.
I believe the Webasto RV heating device and the Aqua-hot are two different animals. Someone more knowledgeable needs to chime in to educate us.