Follow the documentation for creating a part from scratch. The documentation “highly recommends” publishing the part using the default symbol. It is noted that the default symbol’s pins can be reordered setting the “Terminal Order” property for each terminal. However, despite setting the Terminal Order property from 1 to, for example, 16 for each of 16 Terminals, the pin ordering of the published component still uses alphabetical sorting. This issue was reproduced on Windows in Edge and Firefox.

The “Terminal Order” property does not seem to work as the documentation says it should.