XnView Software

maybe there is the problem with code page of characters in IPTC description field? I describe photos in Polish.

I edited IPTC field "description" in my photos using Xnview. When I look at them in Picasa I don't see full written text. Only some letters or words.
Other applications like Irfanview, Exifer see full text in this field of my photos.
Are there any problems with writing in standard form this IPTC ...