[Zope] ZClass inheritance

[Patrick Stinson]

why is it that this doesn't set the inherited site_url property in the newly
created instance of PK_MusicTrack?

request = context.REQUEST
instance = container.PK_MusicTrack.createInObjectManager(request['id'],
request)
request.set('site_url', instance.absolute_url())
instance.propertysheets.common.manage_editProperties(request)


I realize that if PK_MusicTrack inherits site_url, it won't be in
propertysheets.common, but HOW do you set it then?