My diesel filler cap on my 2004 Fiat Ducato, Dethleffs Globetrotter Advantage has seized up and just will not lock anymore. Just falls out of the pipe ! Can I get a replacement ? "NO" is the answer so far ! It used to be part no. 1333085080, but that only exists without a barrel, someone suggested smashing the old one to transfer the barrel, but that's the one that seized up ! Then I was told about part no. 5907613, but that only fits models up to 2003. Then there was a glimmer of hope with part no. 5907582, but they stopped making that in 2008. Has anyone else had this problem, and is there an accessory disel locking cap for my 2004 Fiat Ducato ? Denny.