Not sure if this is actually either a 'plugin' or a 'unicode' issue.

I have a considerable number of travel photographs, which are labelled using local spellings of place names where possible. I do not use non-Roman alphabets (Greek, Cyrillic etc.) but there are accented and special characters within the 'Roman' alphabet in the various European languages (French, Spanish, Scandinavian etc.).

I have found that these do not appear correctly in IPTC titles and captions in IrfanView, and consequently in slideshows drawn from them. This is not the case in other products using exactly the same picture files (eg Picasa, Windows). The only exception appears to be the German 'umlaut'. The filenames themselves including these same characters appear correctly.

If I tick the box ' Load Unicode Plugin at program start... ' in the 'languages' tab of options, the titles and captions now appear correctly (except, this time, umlaut characters!) but the filenames are then misrepresented and unusable to import into slideshows etc.

Incidentally, there does not seem to be a 'Unicode plugin' as such.

How can I get these characters to appear correctly both in filenames AND IPTC metadata simultaneously?