Finally I found a tool to remove the DRM from my WMA-files. Via my internet provider I can download a couple of songs each month. The bad thing is that I could not play these songs on my Ipod since files with DRM can’t be played on a Ipod. Now I can remove the DRM with this tool and convert it to the AAC format or just play the WMA from my Ipod . One remark, you need to have the right to play the file, if you don’t have the license the tool don’t work

You can download the tool here

PS It runs fine in WINE