Enclosure URL formatting

For the uploaded audio file «U Got Me (Burnin').m4a» this is the URL enclosure found in the iTunes RSS feed :
<enclosure url="http://example.com/files/podcast_audio/U Got Me (Burnin&#039;).m4a" length="4333779" type="audio/mpeg" />

So iTunes returns this error after trying to retrieve the enclosure :
«The URL "http://example.com/files/podcast_audio/U Got Me (Burnin').m4a" could not be found on the server.»

The proper URL enclosure should have been :
<enclosure url="http://example.com/files/podcast_audio/U%20Got%20Me%20%28Burnin&#039;%29.m4a" length="4333779" type="audio/mpeg" />

Here is the fix. In script itunes.module [line 146] replace :
'url' => file_create_url($file['filepath']),
with :
'url' => str_replace(' ','%20',str_replace('%','%25',file_create_url($file['filepath']))),

Then, it works!