[TYPO3-english] tesseract filter

[Christoph Holtermann]

Hello !

I've got a second question regarding tesseract data filter and form
sysext. (Tutorial is http://www.typo3-tesseract.com/en/tutorials/advanced-filtering/ )
I want to filter dates (from table tx_cal_event like "20091101").
Extension form lets me force date as input "01-01-2012". When
I tell the filter to compare ( start_date > gp:tx_form|feld ) where
feld is the input field. This comparison doesn't work. I guess I need
to convert values but I don't have a clue how to use conversion
functions in filter. Can someone lend a hand ?

regards,

C. Holtermann