Maybe I wasn´t precise enough. I don´t think that there is something wrong with mimedecode. Apparently it works for many people. But definitely there is a problem with the interaction of the WP-Mail-Hack and i.e. the SE T610 cell phone. I cannot change the way my cell phone is sending emails but there could be a chance to get it working by modifying the WP-Hack. That is why I was thinking about mimedecode.
Has anybody figured out how to post photos by using a cell phone? I have the same problem as Hans-Göran Puke. When I send an email with an attached photo from my SE T610 only the text part shows up in the blog. There seems to be a problem with mimedecode.