Digital BW, The Print

This is terribly off-topic, but I have seen so much discussed about Epson ink cartridges and their compatibility with various printers that I am hoping someone may have the expertise to answer my question.
I have an Epson Stylus Photo R270 (6-color Claria) printer. This seems to be the same as the R260 (U.S. model).
My local dealer stopped carrying inks for the printer, so I had a friend bring me a couple of sets of R260 inks from the US.
While physically identical to my original ink cartridges, these US cartridges are not being recognized by my printer.
I see third party ink cartridges advertised "for R260/R265/R270 printers", seeming to mean they will work in either the R260 or the R270.
Is there anything I can do to make my printer accept these US cartridges? I thought of exchanging the chips but it turns out they are slightly different sizes on the T077 (US) and T081 (foreign) cartridges.
Any ideas?
 
Regards,
Hassan