Hi all. I know we have some pen aficionados here, so I thought this would be a good place to ask. I recently bought a Pilot Duet fountain pen. Of course, Pilot no longer makes any fountain pens except for the disposable Varsity line. What baffles me is that I can't seem to find any cartridges for the pen anywhere. Not on eBay and not from any retailer I can find. Can anybody help me find cartridges for the pen?