Is is possible to subscribe to a podcast that requires a username and password with amarok?

I have tried:

rss://yourusername:password@therssurl.rss
yourusername:password@therssurl
therssurl (then wait for it to ask for a pass)

and it just says: podcast has returned invalid data.

Am I doing it wrong or does Amarok not support this?

Does the url have to be a certain way?:
http://www.pizza.com/
www.pizza.com
pizza.com

Thanks!