[Zope] Change properties

Hi I think i have tried almost all, and i still can't solve a simple problem. I have made a ZClass with some extra properties, and I have to make a form in a DTMLMethod which can change the values of the properties. I have made the form and have tried to make the "update-script" like this: <dtml-var standard_html_header> <dtml-call "propertysheets.zpro.manage_changeProperties({'beskrivelse':'new_beskriv else'})"> <dtml-var standard_html_footer> There are no errors, but the property is not changed. What am i doing wrong??? Thank's in advance Jens Bjerre