[Zope-CMF] Plone + zpt + python scripts: need help

[alienoid]

Hello zope-cmf users,

I need to write ZPT page inside Plone site. This page will call
different python scripts.

>From ZMI I add plone site.
Inside plone side I create PloneFolder and inside that folder I add
default page (I do it from plone site, not from ZMI to not break the
skin) and python script from ZMI. After that I begin add in default
page different TAL expressions that call my python script, but I can
see that this page does not call my script. I have tried stub
expression - <span tal:content="user/getUserName">TEST</span>, but it
renders TEST and not user name. My simple python script returns just a
string, but I can't see it.
What am I missing? What should I do to call my script? (I use standard
TAL expressions that works in plain Zope)

Thanks in advance for your help.

-- 
Best regards,
 alienoid                          mailto:alienoid@is.lg.ua