Sorry Mickey Mouse - I just put the Singapore version in the V804SS phone and everything is now working well. Seems like the China version has a problem with syncing and I believe its the modem setting which is wrong.
So I am not going to risk putting the Japanese version on my phone since with the Singapore version it now has all the features I need and wanted when I got the phone.
Thanks just the same - maybe someone else looking to convert his Z540 to a V804SS with JP might venture into trying this firmware.
mesd/