[Zope] adding a line to a property using DTML

[Martin Dougiamas]

It's the simple things that stump!

Is it possible in DTML to easily add a line to a property of 
type 'lines' ?  (I can do it using external methods but would rather not)

ie something like:

   <!--#call "manage_addProperty('items', '', 'lines')"-->
   <!--#call "manage_changeProperties( items = items + 'something new' ) "-->

keeps giving me 

   "Error value: illegal argument type for built-in operation"

Cheers,
Martin