Go to http://soundcloud.com/you/apps (you must have a Soundcloud account and the Audio module)
Click on “Register a new app”, then enter the name of your Soundcloud application (the name of your edition for example), then complete the fields.
For “redirect uri” enter this address after having replace “url-of-your-edition” by the url of your own QuieroApps edition : http://url-of-your-edition/media/application_gallery_music/soundcloudcallback
For example, if your QuieroApps URL is http://my.apps.com, the address is http://my.apps.com/media/application_gallery_music/soundcloudcallback.
And you are done.