[Google-Desktop] Searching PDF documents written in polish using GDS application.

I am using "Google Desktop Search" for searching documents in
different formats, among them are PDF documents. Unless I use words
with polish letters i.e.: a, c, e, l, n, s, ó, z, z, A, C,
E, L, N, S, Ó, Z, Z, I have no problem, but words with the
letters mentioned cannot be found by the GDS. I think, that the problem
lies in font encoding, because in PDF files there is something like
"Type 1" encoding, while in Windows something like "True Type"
is used.
Not only it isn't possible to find words with polish letters in
"Google Desktop Search" but using find and search boxes in Adobe or
Foxit, which applications I use, I am either not able to find words
with polish letters. I must point it out, that, as far as Adobe Reader
is concerned, I have installed the newest release with polish fonts,
that is CE version, so the text is displayed as it should be. Please
anybody, who can help me, answer what can I do with the problem. I have
thousands of documents in different formats .doc, .xls, .pdf and do not
want to convert PDF files to any other format.
With regards,
Elemelek