Don't know what version of windows you use, but there is no "server properties" item in any of the menus for any printers in XP. I do see that the KB article seems to indicate there is, but I've never seen that in any version of Windows, and they still don't specify what version it applies to, making me think it only shows that when Publisher is installed (but that'd be weird).
It does however specifically state that you're adding it to the printer driver's list of available paper sizes, so it's still just using the driver to specify a size. That still doesn't help you to "export" the sizes so you can easily copy them.
Ugh, nevermind, I found the server properties page (I forget I use the expanded menus). This is creating the forms directly in the "print server" subsystem. Don't know where it would save that information. The list stored there seems to be what the print server makes available for a specific driver to select from. However it seems to only be applicable to "generic" drivers built into Windows. When I create a new form, it doesn't show up in the Epson list. The article does mention it's for if you use a generic driver; generic drivers won't have any special formatting options so the print server can supply all the formatting.