Default printer does not appear in custom-sized templates

Question

I posted this question in the 'Pages' community, but received no replies, so I am possting it again here.
I now have an Epson XP-750 printer-scanner. I have set it as my default printer in System Preferences. When I create a document in Pages whose paper size is one of the standard ones catered for by the XP-750 or open a previously saved one in one of those sizes, or I open a document from one of the templates provided by Pages, the printer shown in Page Setup is always the XP-750. But if I create a document in a custom size (such as a 9 cm x 14 cm correspondence card), Page Setup shows 'Any Printer' until I re-set it to 'XP-750', and even if I save the document or save it as a template and then re-open it, the printer is always shown as 'Any Printer'.
Is there any way of making the XP-750 'stick' as the printer shown in Page Setup even in these custom documents?

Answer 1

Thanks for this, Joe Bailey. I am ignorant of programming and cerainly wouldn't dream of trying to make such a modification. But the interesting thing is that if I create a document in MS Word and give it a custom size, the printer's name and paper size are retained after saving, closure and re-opening, though they are not retained in Pages.
I want to use Pages for my custom-sized correspondence cards because the database that I use for mail merge is in Numbers. I suppose I could export it as Excel and use that with a Word correspondence card, but it all gets a bit messy, especially when it comes to updating the database, and will be a lot of work, as I have several such cards with different letter-heads, etc.
I contacted Epson about this problem, and they said it was a matter for the application in which the custom-sized document was created — i.e. Pages in my case — so according to Epson it is not a matter of the printer driver.