My apologies - I'm an infrequent visitor and didn't see that there had been replies to my post. As I recall I did some searching at the time and couldn't find any indication that M. Huet still produces his inks or that anyone else now offers the range.
The chap who runs AMF87 is quite helpful and may be able to advise (although I've always communicated with him in French, so I don't know how good his English may be). Have you tried the SNCF Society? Modellers there may also be able to help.