Hallo,
To get the simple non-framed page I just added the condition in
main_template:
<body tal:condition="not:python:here.REQUEST.has_key('printable')">
...
<body>
<body tal:condition="python:here.REQUEST.has_key('printable')"">
"""'The last part of the original <body> without framing"""
</body>
Pawel