Content Management System

Hi bidders. I need a backoffice for a flash website i'm developing. This website's content is based on XML, which is read by Flash, but as i'm not into PHP and a CMS was asked, here i am asking for your help. Basically I need it to write on a predefined XML format, that my flash website will read. I would also like this backoffice to have a way to upload mp3 and photos and/or read them from a directory for later use. The basics is as attached on the text file, which includes XML examples to what i want. If you think its too much work for the budget (i know its low, sorry...), you can do a couple of examples and just explain me how to make new ones, as the code should be always the same, and i can reutilize your code to finish the cms. Best regards and happy bidding. Oh, and the only thing i really need is to use an IM software such as MSN or simmilar. This is a bit urgent.