PRS-T1 Sony PRS-T1 && DRM protected epub files

Hello,

I own now a PRS-T1 and it works fine with Wifi, with my own PDF files etc.
Yesterday I bought my first eBook in
http://ebooks.fnac.es/el-sistema-vic.../9788420402550 and after the payment I've got a download link to some file 'URLLink.acsm' (attached as XML). The file contains a link to a xxxx.epub file which I could download as well. But this is somehow DRM protected. The bookseller says that I need Adobe Digital Editions for this :angry:

How can I open this or at least transform it to PDF?

Thanks

matthias