Hi! I found exactly what I needed!!
http://www.spencernetwork.org/jcode-LE/
There are a functions to convert from/to EUC-JP, Shift_JIS & ISO-2022-JP(JIS) and others to convert from/to full-width & half-width character.
I didn't find time to test it yet. The documentation is in Japanese but I can make a translation if anyone is interested in it.
I've thought about separators in Japanese. There is half and full-width space, half and full-width period, half and full-width comma, half and full-width apostrophe, ...
Can I add several separator in the same string? I guess I must enter unencoded characters e.g. @ for full-width space, correct? Or do I need to separate each separator by a sign (comma...)?
BTW, thanks for your help Charter.
It's greatly appreciated.