Podcast Producer notify iTunes U Question

Hi,

We have recently installed podcast producer and have got plenty workflows etc set up.
In the 'Notify' part in Podcast Composer there is an option for iTunes U. It asks for "iTunes U site to update with podcast library"... I have entered in our institutions URL but that's all I seem to be able to do.
How can I get podcast producer to add content to our iTunes U site? We only have a public site at the moment, does this matter?

Thanks in advance,

Nathan.