Swedish translation characters ö, å, Ä = ?

Hi everyone,

for those who don't want to read my whole post here's my summary: basically the swedish characters ö, å, Ä are not working in my translation and are showing as a ? (question mark). if you can help or are interested read more please!

i've been with drupal for awhile now but i've only just delved into the world of translations!
My client who is swedish wants his site in swedish, so i got a copy of the latest swedish translation for drupal which is brilliant god knows what i would have done without it!! No problems there!

I have a few custom modules so i ran the extractor.php to get the .pot file, i looked through the file to check there are no errors and it all looks good! I mail it from to my client for translation (he used notepad to input the swedish versions of strings, saved the file and sent it back to me, could that have messed up the encoding?). He's done the translation into swedish that i uploaded through the locale module but all the references to the characters ö, å, Ä are replaced with a ? (question mark). It seems wierd to me as the swedish translation for the core drupal files works fine. i've searched everywhere, am i doing something wrong?? could the problem be caused by my client emailing me back the .po file??

i can go through and manually change the ? to the appropiate swedish character but i really want to know why my translation is not working properly, so if anyone out there can help or has had a similar experience i loved any advice!!

any help or suggestions would be brilliant.

thanks
Tom