Control over empty lines at beginning page

Hello, I have a stylesheet that outputs an empty block like the following: when I want some space between blocks (empty lines). I do not want this space if the above mentioned block occurs at the beginning of a page. I read in the XSL FO specification that space-before.condit

The text renderer errors out when it encounters a positioned block-container

This isn't a show stopper in any way since I can render text without FOP. I added a positioned block-container to my .FO. Now the text renderer bombs on that page. Is there any way to include a positioned block-container that does not crash the text renderer? Chuck value: FOP 0.20.2 OS Windows 2