My b2evolution Version: Not Entered

Hi, Hopefully someone will be able to help me with this. I want to provide iTunes with a feed for a video podcast. I've created my podcast posts and submitted the feed to Feed Validator but it throws an error saying Missing enclosure attribute: length and Missing enclosure attribute: type. According to the documentation these should be length in bites and the type (video) but how do I specify this in B2E?

using 4.0.5.

thanks