The page uses a Java applet, which probably has some way of getting printer details. Java being cross-platform, it probably just checks for "OneNote" in the printer's name, so try renaming the printer. But it could be that the checks are more advanced.
In any case, you can install printers that are not connected – can't remember exactly how, but the "Add printer" program should offer this option. Once you have a "real" printer, existing or not, the Print dialog should have a checkbox named "Print to file". What would otherwise be sent to a printer, will appear as a
.prn file which you can send to the actual printer later. (The disadvantage of this, however, is that you cannot display it on-screen, and your actual printer must support the exact same set commands as the one you installed. If Windows offers a PostScript printer driver, try it.)