[Zope] Adding to an XMLDocument through web forms

Hi, I`m looking for a way to give a user the ability to add new data to an XMLDocument through web forms, does anyone have experience of this or would be able to point me in the direction of an example or howto? I have a file similar to: <channel> <event> ... </event> <announcement> ... </announcement> </channel> So i`d have two web forms, one to add a new <event> and another to add an <announcement>, taking the data from a form is obviously simple but adding this to my XMLDocument has stumped me. Any help would be appreciated. Ian